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data/mdn-content/files/en-us/webassembly/reference/memory | data/mdn-content/files/en-us/webassembly/reference/memory/size/index.md | ---
title: Size
slug: WebAssembly/Reference/Memory/Size
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`size`** instruction, returns the amount of pages the memory instance currently has, each page is sized 64KiB.
{{EmbedInteractiveExample("pages/wat/size.html", "tabbed-standard")}}
## Syntax
```wasm
;; get the amount of pages the memory has
memory.size
```
| Instruction | Binary opcode |
| ------------- | ------------- |
| `memory.size` | `0x3f` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/memory | data/mdn-content/files/en-us/webassembly/reference/memory/load/index.md | ---
title: Load
slug: WebAssembly/Reference/Memory/Load
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`load`** instructions, are used to load a number from memory onto the stack.
For the integer numbers, you can also load a narrower number from memory and extend it into a wider type, e.g. load an unsigned 8-bit number and convert it into an i32 (**`i32.load8_u`**). These instructions are separate for signed and unsigned numbers.
{{EmbedInteractiveExample("pages/wat/load.html", "tabbed-taller")}}
## Syntax
```wasm
;; the offset from where to load the number
i32.const 0
;; load the number at position 0
i32.load
```
| Instruction | Binary opcode |
| -------------- | ------------- |
| `i32.load` | `0x28` |
| `i64.load` | `0x29` |
| `f32.load` | `0x2a` |
| `f64.load` | `0x2b` |
| `i32.load8_s` | `0x2c` |
| `i32.load8_u` | `0x2d` |
| `i32.load16_s` | `0x2e` |
| `i32.load16_u` | `0x2f` |
| `i64.load8_s` | `0x30` |
| `i64.load8_u` | `0x31` |
| `i64.load16_s` | `0x32` |
| `i64.load16_u` | `0x33` |
| `i64.load32_s` | `0x34` |
| `i64.load32_u` | `0x35` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/memory | data/mdn-content/files/en-us/webassembly/reference/memory/fill/index.md | ---
title: Fill
slug: WebAssembly/Reference/Memory/Fill
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`fill`** instruction sets all bytes in a memory region to a given byte.
The **`fill`** instruction does not return a value. If the memory region indicated is out of bounds this instruction will trap.
## Syntax
```wasm
;; The pointer to the region to update
i32.const 200
;; The value to set each byte to (must be < 256)
i32.const 255
;; The number of bytes to update
i32.const 100
;; Update the target region
memory.fill
```
| Instruction | Binary opcode |
| ------------- | ------------- |
| `memory.fill` | `0xFC 0x0b` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/memory | data/mdn-content/files/en-us/webassembly/reference/memory/copy/index.md | ---
title: Copy
slug: WebAssembly/Reference/Memory/Copy
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`copy`** instruction copies data from one region of memory to another.
The **`copy`** instruction does not return a value. If either the source or destination range is out of bounds, the instruction traps.
## Syntax
```wasm
;; Destination address to copy to
i32.const 50
;; Source address to copy from
i32.const 100
;; Number of bytes to copy
i32.const 25
;; Copy data from [100, 125] to [50, 75]
memory.copy
;; the top item on the stack will now either be the previous number of pages (success) or `-1` (failure)
```
| Instruction | Binary opcode |
| ------------- | ------------- |
| `memory.copy` | `0xFC 0x0a` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference | data/mdn-content/files/en-us/webassembly/reference/numeric/index.md | ---
title: WebAssembly numeric instructions
slug: WebAssembly/Reference/Numeric
page-type: landing-page
---
{{WebAssemblySidebar}}
WebAssembly numeric instructions.
## Constants
- [`Const`](/en-US/docs/WebAssembly/Reference/Numeric/Const)
- : Declare a constant numbers.
## Comparison
- [`Equal`](/en-US/docs/WebAssembly/Reference/Numeric/Equal)
- : Check if two numbers are equal.
- [`Not equal`](/en-US/docs/WebAssembly/Reference/Numeric/Not_equal)
- : Check if two numbers are not equal.
- [`Greater than`](/en-US/docs/WebAssembly/Reference/Numeric/Greater_than)
- : Check if a number is greater than another number.
- [`Less than`](/en-US/docs/WebAssembly/Reference/Numeric/Less_than)
- : Check if a number is less than another number.
- [`Greater or equal`](/en-US/docs/WebAssembly/Reference/Numeric/Greater_or_equal)
- : Check if a number is greater than or equal to another number.
- [`Less or equal`](/en-US/docs/WebAssembly/Reference/Numeric/Less_or_equal)
- : Check if a number is less than or equal to another number.
## Arithmetic
- [`Addition`](/en-US/docs/WebAssembly/Reference/Numeric/Addition)
- : Add up two numbers.
- [`Subtraction`](/en-US/docs/WebAssembly/Reference/Numeric/Subtraction)
- : Subtract one number from another number.
- [`Multiplication`](/en-US/docs/WebAssembly/Reference/Numeric/Multiplication)
- : Multiply one number by another number.
- [`Division`](/en-US/docs/WebAssembly/Reference/Numeric/Division)
- : Divide one number by another number.
- [`Remainder`](/en-US/docs/WebAssembly/Reference/Numeric/Remainder)
- : Calculate the remainder left over when one integer is divided by another integer.
## Conversion
- [`Extend`](/en-US/docs/WebAssembly/Reference/Numeric/Extend)
- : Convert (extend) `i32` to `i64`.
- [`Wrap`](/en-US/docs/WebAssembly/Reference/Numeric/Wrap)
- : Convert (wrap) `i64` to `i32`.
- [`Promote`](/en-US/docs/WebAssembly/Reference/Numeric/Promote)
- : Convert (promote) `f32` to `f64`.
- [`Demote`](/en-US/docs/WebAssembly/Reference/Numeric/Demote)
- : Convert (demote) `f64` to `f32`.
- [`Convert`](/en-US/docs/WebAssembly/Reference/Numeric/Convert)
- : Convert integers to floating points.
- [`Truncate (float to int)`](/en-US/docs/WebAssembly/Reference/Numeric/Truncate_float_to_int)
- : Convert (truncate fractional part) floating points to integers.
- [`Reinterpret`](/en-US/docs/WebAssembly/Reference/Numeric/Reinterpret)
- : Reinterpret the bytes of integers as floating points and vice versa.
## Floating point specific instructions
- [`Min`](/en-US/docs/WebAssembly/Reference/Numeric/Min)
- : Get the lower of two numbers.
- [`Max`](/en-US/docs/WebAssembly/Reference/Numeric/Max)
- : Get the higher of two numbers.
- [`Nearest`](/en-US/docs/WebAssembly/Reference/Numeric/Nearest)
- : Round a number to the nearest integer.
- [`Ceil`](/en-US/docs/WebAssembly/Reference/Numeric/Ceil)
- : Round up a number.
- [`Floor`](/en-US/docs/WebAssembly/Reference/Numeric/Floor)
- : Round down a number.
- [`Truncate (float to float)`](/en-US/docs/WebAssembly/Reference/Numeric/Truncate_float_to_float)
- : Discard the fractional part of a number.
- [`Absolute`](/en-US/docs/WebAssembly/Reference/Numeric/Absolute)
- : Get the absolute value of a number.
- [`Negate`](/en-US/docs/WebAssembly/Reference/Numeric/Negate)
- : Negate a number.
- [`Square root`](/en-US/docs/WebAssembly/Reference/Numeric/Square_root)
- : Get the square root of a number.
- [`Copy sign`](/en-US/docs/WebAssembly/Reference/Numeric/Copy_sign)
- : Copy just the sign bit from one number to another.
## Bitwise
- [`AND`](/en-US/docs/WebAssembly/Reference/Numeric/AND)
- : Used for performing a bitwise AND.
- [`OR`](/en-US/docs/WebAssembly/Reference/Numeric/OR)
- : Used for performing a bitwise OR.
- [`XOR`](/en-US/docs/WebAssembly/Reference/Numeric/XOR)
- : Used for performing a bitwise XOR.
- [`Left shift`](/en-US/docs/WebAssembly/Reference/Numeric/Left_shift)
- : Used for performing a bitwise left-shift.
- [`Right shift`](/en-US/docs/WebAssembly/Reference/Numeric/Right_shift)
- : Used for performing a bitwise right-shift.
- [`Left rotate`](/en-US/docs/WebAssembly/Reference/Numeric/Left_rotate)
- : Used for performing a bitwise left-rotate.
- [`Right rotate`](/en-US/docs/WebAssembly/Reference/Numeric/Right_rotate)
- : Used for performing a bitwise right-rotate.
- [`Count leading zeros`](/en-US/docs/WebAssembly/Reference/Numeric/Count_leading_zeros)
- : Count the amount of leading zeros in a numbers binary representation.
- [`Count trailing zeros`](/en-US/docs/WebAssembly/Reference/Numeric/Count_trailing_zeros)
- : Count the amount of trailing zeros in a numbers binary representation.
- [`Population count`](/en-US/docs/WebAssembly/Reference/Numeric/Population_count)
- : Count the total amount of 1s in a numbers binary representation.
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/right_rotate/index.md | ---
title: Right rotate
slug: WebAssembly/Reference/Numeric/Right_rotate
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`rotr`** instructions, short for _rotate-right_, are used for performing a bitwise right-rotate.
{{EmbedInteractiveExample("pages/wat/rotr.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 7 ;; 00000000_00000000_00000000_00000111
i32.const 1 ;; right rotate one spot
;; perform a bitwise right-rotate
i32.rotr
;; the top item on the stack will now be 2147483651
;; (10000000_00000000_00000000_00000011)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.rotr` | `0x78` |
| `i64.rotr` | `0x8a` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/greater_or_equal/index.md | ---
title: Greater or equal
slug: WebAssembly/Reference/Numeric/Greater_or_equal
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`ge`** instructions, short for _greater or equal_, check if a number is greater than or equal to another number. If the first number is greater than or equal to the second number equal `1` will be pushed on to the stack, otherwise `0` will be pushed on to the stack.
The integer types have separate greater or equal instructions for signed (**`ge_s`**) and unsigned (**`ge_u`**) numbers.
{{EmbedInteractiveExample("pages/wat/ge.html", "tabbed-taller")}}
## Syntax
```wasm
;; load 2 numbers on to the stack
local.get $num
i32.const 2
;; check if $num is greater than or equal to '2'
i32.ge_u
;; if $num is greater than or equal to the `2`, `1` will be pushed on to the stack,
;; otherwise `0` will be pushed on to the stack.
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.ge_s` | `0x4e` |
| `i32.ge_u` | `0x4f` |
| `i64.ge_s` | `0x59` |
| `i64.ge_u` | `0x5a` |
| `f32.ge` | `0x60` |
| `f64.ge` | `0x66` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/not_equal/index.md | ---
title: Not equal
slug: WebAssembly/Reference/Numeric/Not_equal
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`ne`** instructions, short for _not equal_, check if two numbers are not equal. If the numbers are not equal `1` will be pushed on to the stack, otherwise `0` will be pushed on to the stack.
{{EmbedInteractiveExample("pages/wat/ne.html", "tabbed-taller")}}
## Syntax
```wasm
;; load 2 numbers on to the stack
local.get $num
i32.const 2
;; check if $num is not equal to '2'
i32.ne
;; if $num is not equal to `2`, `1` will be pushed on to the stack,
;; otherwise `0` will be pushed on to the stack.
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.ne` | `0x47` |
| `i64.ne` | `0x52` |
| `f32.ne` | `0x5c` |
| `f64.ne` | `0x62` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/wrap/index.md | ---
title: Wrap
slug: WebAssembly/Reference/Numeric/Wrap
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`wrap`** instruction, is used to convert numbers of type `i64` to type `i32`. If the number is larger than what an `i32` can hold this operation will wrap, resulting in a different number.
One can think of wrap either as reducing the value [mod](https://en.wikipedia.org/wiki/Modular_arithmetic) 2<sup>32</sup>, or as discarding the high 32 bits to produce a value containing just the low 32 bits.
{{EmbedInteractiveExample("pages/wat/wrap.html", "tabbed-taller")}}
## Syntax
```wasm
;; push an i64 onto the stack
i64.const 10
;; wrap from i64 to i32
i32.wrap_i64
;; the top item on the stack will now be the value 10 of type `i32`
```
| Instruction | Binary opcode |
| -------------- | ------------- |
| `i32.wrap_i64` | `0xa7` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/remainder/index.md | ---
title: Remainder
slug: WebAssembly/Reference/Numeric/Remainder
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`rem`** instructions, short for _remainder_, are used to calculate the remainder left over when one integer is divided by another integer, similar to the **`%`** operator in other languages. The **`rem`** instructions are only available for the integer types and not for the floating point types.
{{EmbedInteractiveExample("pages/wat/rem.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 10
i32.const 3
;; calculate the remainder of dividing one number by the other
i32.rem
;; the top item on the stack will now be 1 (10 % 3 = 1)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.rem_s` | `0x6f` |
| `i32.rem_u` | `0x70` |
| `i64.rem_s` | `0x81` |
| `i64.rem_u` | `0x82` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/floor/index.md | ---
title: Floor
slug: WebAssembly/Reference/Numeric/Floor
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`floor`** instructions, are used for getting the value of a number rounded down to the next integer.
**`floor`** differs from **`trunc`** when used on negative numbers, **`floor`** will round down in those cases while **`trunc`** will round up.
{{EmbedInteractiveExample("pages/wat/floor.html", "tabbed-standard")}}
## Syntax
```wasm
;; load a number onto the stack
f32.const -2.7
;; round down
f32.floor
;; the top item on the stack will now be -3
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `f32.floor` | `0x8e` |
| `f64.floor` | `0x9c` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/or/index.md | ---
title: OR
slug: WebAssembly/Reference/Numeric/OR
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`or`** instructions, are used for performing a bitwise OR, similar to the **`|`** operator in other languages.
{{EmbedInteractiveExample("pages/wat/or.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 5 ;; 00000101
i32.const 3 ;; 00000011
;; perform a bitwise OR
i32.or
;; the top item on the stack will now be 7 (00000111)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.or` | `0x72` |
| `i64.or` | `0x84` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/and/index.md | ---
title: AND
slug: WebAssembly/Reference/Numeric/AND
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`and`** instructions, are used for performing a bitwise AND, similar to the **`&`** operator in other languages.
{{EmbedInteractiveExample("pages/wat/and.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 5 ;; 00000101
i32.const 3 ;; 00000011
;; perform a bitwise AND
i32.and
;; the top item on the stack will now be 1 (00000001)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.and` | `0x71` |
| `i64.and` | `0x83` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/xor/index.md | ---
title: XOR
slug: WebAssembly/Reference/Numeric/XOR
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`xor`** instructions, are used for performing a bitwise XOR, similar to the **`^`** operator in other languages.
{{EmbedInteractiveExample("pages/wat/xor.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 5 ;; 00000101
i32.const 3 ;; 00000011
;; perform a bitwise XOR
i32.xor
;; the top item on the stack will now be 6 (00000110)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.xor` | `0x73` |
| `i64.xor` | `0x85` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/count_leading_zeros/index.md | ---
title: Count leading zeros
slug: WebAssembly/Reference/Numeric/Count_leading_zeros
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`clz`** instructions, short for _count leading zeros_, are used to count the amount of zeros at the start of the numbers binary representation.
{{EmbedInteractiveExample("pages/wat/clz.html", "tabbed-taller")}}
## Syntax
```wasm
;; load a number onto the stack
i32.const 8388608 ;; 00000000_10000000_00000000_00000000
;; count leading zeros
i32.clz
;; the top item on the stack will now be 8
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.clz` | `0x67` |
| `i64.clz` | `0x79` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/less_or_equal/index.md | ---
title: Less or equal
slug: WebAssembly/Reference/Numeric/Less_or_equal
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`le`** instructions, short for _less or equal_, check if a number is less than or equal to another number. If the first number is less than or equal to the second number equal `1` will be pushed on to the stack, otherwise `0` will be pushed on to the stack.
The integer types have separate less or equal instructions for signed (**`le_s`**) and unsigned (**`le_u`**) numbers.
{{EmbedInteractiveExample("pages/wat/le.html", "tabbed-taller")}}
## Syntax
```wasm
;; load 2 numbers on to the stack
local.get $num
i32.const 2
;; check if $num is less then or equal to '2'
i32.le_u
;; if $num is less than or equal to the `2`, `1` will be pushed on to the stack,
;; otherwise `0` will be pushed on to the stack.
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.le_s` | `0x4C` |
| `i32.le_u` | `0x4D` |
| `i64.le_s` | `0x57` |
| `i64.le_u` | `0x58` |
| `f32.le` | `0x5F` |
| `f64.le` | `0x65` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/population_count/index.md | ---
title: Population count
slug: WebAssembly/Reference/Numeric/Population_count
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`popcnt`** instructions, short for _population count_, are used to count the amount of `1`s in a numbers binary representation.
{{EmbedInteractiveExample("pages/wat/popcnt.html", "tabbed-taller")}}
## Syntax
```wasm
;; load a number onto the stack
i32.const 130 ;; 10000010
;; count the 1s
i32.popcnt
;; the top item on the stack will now be 2
```
| Instruction | Binary opcode |
| ------------ | ------------- |
| `i32.popcnt` | `0x69` |
| `i64.popcnt` | `0x7b` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/negate/index.md | ---
title: Negate
slug: WebAssembly/Reference/Numeric/Negate
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`neg`** instructions, short for _negate_, are used to negate a number. That is, turn a positive number into a negative number and a negative number into a positive number.
{{EmbedInteractiveExample("pages/wat/neg.html", "tabbed-standard")}}
## Syntax
```wasm
;; load a number onto the stack
f32.const 2.7
;; negate
f32.neg
;; the top item on the stack will now be -2.7
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `f32.neg` | `0x8c` |
| `f64.neg` | `0x9a` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/equal/index.md | ---
title: Equal
slug: WebAssembly/Reference/Numeric/Equal
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`eq`** instructions, short for _equal_, check if two numbers are equal. If both numbers are equal `1` will be pushed on to the stack, otherwise `0` will be pushed on to the stack.
Similarly, the **`eqz`** instructions check if a number is equal to zero, the **`eqz`** instructions are only available for the integer types and not for the floating point types.
{{EmbedInteractiveExample("pages/wat/eq.html", "tabbed-taller")}}
## Syntax
```wasm
;; load 2 numbers on to the stack
local.get $num
i32.const 2
;; check if $num is equal to '2'
i32.eq
;; if $num is equal to `2`, `1` will be pushed on to the stack,
;; otherwise `0` will be pushed on to the stack.
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.eqz` | `0x45` |
| `i32.eq` | `0x46` |
| `i64.eqz` | `0x50` |
| `i64.eq` | `0x51` |
| `f32.eq` | `0x5b` |
| `f64.eq` | `0x61` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/extend/index.md | ---
title: Extend
slug: WebAssembly/Reference/Numeric/Extend
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`extend`** instructions, are used to convert (extend) numbers of type `i32` to type `i64`. There are signed and unsigned versions of this instruction.
{{EmbedInteractiveExample("pages/wat/extend.html", "tabbed-taller")}}
## Syntax
```wasm
;; push an i32 onto the stack
i32.const 10
;; sign-extend from i32 to i64
i64.extend_i32_s
;; the top item on the stack will now be the value 10 of type i64
```
| Instruction | Binary opcode |
| ------------------ | ------------- |
| `i64.extend_i32_s` | `0xac` |
| `i64.extend_i32_u` | `0xad` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/multiplication/index.md | ---
title: Multiplication
slug: WebAssembly/Reference/Numeric/Multiplication
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`mul`** instructions, short for _multiplication_, are used for multiplying one number by another number, similar to the **`*`** operator in other languages.
{{EmbedInteractiveExample("pages/wat/mul.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 10
i32.const 3
;; multiply one number by the other
i32.mul
;; the top item on the stack will now be 30 (10 * 3 = 30)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.mul` | `0x6c` |
| `i64.mul` | `0x7e` |
| `f32.mul` | `0x94` |
| `f64.mul` | `0xa2` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/ceil/index.md | ---
title: Ceil
slug: WebAssembly/Reference/Numeric/Ceil
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`ceil`** instructions, are used for getting the value of a number rounded up to the next integer.
{{EmbedInteractiveExample("pages/wat/ceil.html", "tabbed-standard")}}
## Syntax
```wasm
;; load a number onto the stack
f32.const 2.7
;; round up
f32.ceil
;; the top item on the stack will now be 3
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `f32.ceil` | `0x8d` |
| `f64.ceil` | `0x9b` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/greater_than/index.md | ---
title: Greater than
slug: WebAssembly/Reference/Numeric/Greater_than
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`gt`** instructions, short for _greater than_, check if a number is greater than another number. If the first number is greater than the second number equal `1` will be pushed on to the stack, otherwise `0` will be pushed on to the stack.
The integer types have separate greater than instructions for signed (**`gt_s`**) and unsigned (**`gt_u`**) numbers.
{{EmbedInteractiveExample("pages/wat/gt.html", "tabbed-taller")}}
## Syntax
```wasm
;; load 2 numbers on to the stack
local.get $num
i32.const 2
;; check if $num is greater than '2'
i32.gt_u
;; if $num is greater than the `2`, `1` will be pushed on to the stack,
;; otherwise `0` will be pushed on to the stack.
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.gt_s` | `0x4a` |
| `i32.gt_u` | `0x4b` |
| `i64.gt_s` | `0x55` |
| `i64.gt_u` | `0x56` |
| `f32.gt` | `0x5e` |
| `f64.gt` | `0x64` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/division/index.md | ---
title: Division
slug: WebAssembly/Reference/Numeric/Division
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`div`** instructions, short for _division_, are used for dividing one number by another, similar to the **`/`** operator in other languages.
{{EmbedInteractiveExample("pages/wat/div.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 12
i32.const 3
;; divide one number by the other
i32.div_u
;; the top item on the stack will now be 4 (12 / 3 = 4)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.div_s` | `0x6d` |
| `i32.div_u` | `0x6e` |
| `i64.div_s` | `0x7f` |
| `i64.div_u` | `0x80` |
| `f32.div` | `0x95` |
| `f64.div` | `0xa3` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/promote/index.md | ---
title: Promote
slug: WebAssembly/Reference/Numeric/Promote
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`promote`** instruction, is used to convert (promote) numbers of type `f32` to type `f64`.
{{EmbedInteractiveExample("pages/wat/promote.html", "tabbed-taller")}}
## Syntax
```wasm
;; push an f32 onto the stack
f32.const 10.5
;; promote from f32 to f64
f64.promote_f32
;; the top item on the stack will now be the value 10.5 of type f64
```
| Instruction | Binary opcode |
| ----------------- | ------------- |
| `f64.promote_f32` | `0xbb` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/reinterpret/index.md | ---
title: Reinterpret
slug: WebAssembly/Reference/Numeric/Reinterpret
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`reinterpret`** instructions, are used to reinterpret the bits of a number as a different type.
{{EmbedInteractiveExample("pages/wat/reinterpret.html", "tabbed-taller")}}
## Syntax
```wasm
;; the value `10000000_00000000_00000000_00000000` in binary
;; maps to `-0` as a floating point and to `-2147483648` as an integer
;; push an f32 onto the stack
f32.const -0
;; reinterpret the bytes of the f32 as i32
i32.reinterpret_f32
;; the top item on the stack will now be the value -2147483648 of type i32
```
| Instruction | Binary opcode |
| --------------------- | ------------- |
| `i32.reinterpret_f32` | `0xbc` |
| `i64.reinterpret_f64` | `0xbd` |
| `f32.reinterpret_i32` | `0xbe` |
| `f64.reinterpret_i64` | `0xbf` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/count_trailing_zeros/index.md | ---
title: Count trailing zeros
slug: WebAssembly/Reference/Numeric/Count_trailing_zeros
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`ctz`** instructions, short for _count trailing zeros_, are used to count the amount of zeros at the end of the numbers binary representation.
{{EmbedInteractiveExample("pages/wat/ctz.html", "tabbed-taller")}}
## Syntax
```wasm
;; load a number onto the stack
i32.const 8388608 ;; 00000000_10000000_00000000_00000000
;; count trailing zeros
i32.ctz
;; the top item on the stack will now be 23
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.ctz` | `0x68` |
| `i64.ctz` | `0x7a` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/const/index.md | ---
title: Const
slug: WebAssembly/Reference/Numeric/Const
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`const`** instructions, are used to declare numbers.
{{EmbedInteractiveExample("pages/wat/const.html", "tabbed-standard")}}
## Syntax
```wasm
;; push `5` onto the stack
i32.const 5
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.const` | `0x41` |
| `i64.const` | `0x42` |
| `f32.const` | `0x43` |
| `f64.const` | `0x44` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/right_shift/index.md | ---
title: Right shift
slug: WebAssembly/Reference/Numeric/Right_shift
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`shr`** instructions, short for _shift-right_, are used for performing a bitwise right-shift, similar to the **`>>>`** operator in other languages.
{{EmbedInteractiveExample("pages/wat/shr.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 7 ;; 00000111
i32.const 1 ;; right shift one spot
;; perform a bitwise right-shift
i32.shr_u
;; the top item on the stack will now be 3 (00000011)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.shr_s` | `0x75` |
| `i32.shr_u` | `0x76` |
| `i64.shr_s` | `0x87` |
| `i64.shr_u` | `0x88` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/convert/index.md | ---
title: Convert
slug: WebAssembly/Reference/Numeric/Convert
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`convert`** instructions, are used for converting integer numbers to floating point numbers. There are signed and unsigned versions of this instruction.
{{EmbedInteractiveExample("pages/wat/convert.html", "tabbed-taller")}}
## Syntax
```wasm
;; push an i32 onto the stack
i32.const 10
;; convert from signed i32 to f32
f32.convert_i32_s
;; the top item on the stack will now be the value 10 of type f32
```
| Instruction | Binary opcode |
| ------------------- | ------------- |
| `f32.convert_i32_s` | `0xb2` |
| `f32.convert_i32_u` | `0xb3` |
| `f32.convert_i64_s` | `0xb4` |
| `f32.convert_i64_u` | `0xb5` |
| `f64.convert_i32_s` | `0xb7` |
| `f64.convert_i32_u` | `0xb8` |
| `f64.convert_i64_s` | `0xb9` |
| `f64.convert_i64_u` | `0xba` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/copy_sign/index.md | ---
title: Copy sign
slug: WebAssembly/Reference/Numeric/Copy_sign
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`copysign`** instructions, are used to copy just the sign bit from one number to another.
{{EmbedInteractiveExample("pages/wat/copysign.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
f32.const 10
f32.const -1
;; copy just the sign bit from the second number (-1) to the first (10)
f32.copysign
;; the top item on the stack will now be -10
```
| Instruction | Binary opcode |
| -------------- | ------------- |
| `f32.copysign` | `0x98` |
| `f64.copysign` | `0xa6` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/truncate_float_to_float/index.md | ---
title: Truncate (float to float)
slug: WebAssembly/Reference/Numeric/Truncate_float_to_float
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`trunc`** instructions, short for _truncate_, are used for getting the value of a number without its fractional part.
**`trunc`** differs from **`floor`** when used on negative numbers, **`floor`** will round down in those cases while **`trunc`** will round up.
There's another [**`trunc`**](/en-US/docs/WebAssembly/Reference/Numeric/Truncate_float_to_int) instruction that truncates the fractional part of a floating point and converts it to an integer.
{{EmbedInteractiveExample("pages/wat/trunc_float_to_float.html", "tabbed-taller")}}
## Syntax
```wasm
;; load a number onto the stack
f32.const 2.7
;; discard the fractional part (.7)
f32.trunc
;; the top item on the stack will now be 2
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `f32.trunc` | `0x8f` |
| `f64.trunc` | `0x9d` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/square_root/index.md | ---
title: Square root
slug: WebAssembly/Reference/Numeric/Square_root
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`sqrt`** instructions, short for _square root_, are used to get the square root of a number.
{{EmbedInteractiveExample("pages/wat/sqrt.html", "tabbed-standard")}}
## Syntax
```wasm
;; load a number onto the stack
f32.const 289
;; get the square root of 289
f32.sqrt
;; the top item on the stack will now be 17
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `f32.sqrt` | `0x91` |
| `f64.sqrt` | `0x9f` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/truncate_float_to_int/index.md | ---
title: Truncate (float to int)
slug: WebAssembly/Reference/Numeric/Truncate_float_to_int
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`trunc`** instructions, are used for converting floating points to integers. It's named truncate since it truncates the fractional part of the number when doing the conversion. There are signed and unsigned versions of this instruction.
There's another [**`trunc`**](/en-US/docs/WebAssembly/Reference/Numeric/Truncate_float_to_float) instruction that truncates the fractional part of a floating point without converting it to and integer.
{{EmbedInteractiveExample("pages/wat/trunc_float_to_int.html", "tabbed-taller")}}
## Syntax
```wasm
;; push an f32 onto the stack
f32.const 10.5
;; convert from f32 to signed i32 rounding towards zero (.5 will be lost)
i32.trunc_f32_s
;; the top item on the stack will now be the value 10 of type f32
```
| Instruction | Binary opcode |
| ----------------- | ------------- |
| `i32.trunc_f32_s` | `0xa8` |
| `i32.trunc_f32_u` | `0xa9` |
| `i32.trunc_f64_s` | `0xaa` |
| `i32.trunc_f64_u` | `0xab` |
| `i64.trunc_f32_s` | `0xae` |
| `i64.trunc_f32_u` | `0xaf` |
| `i64.trunc_f64_s` | `0xb0` |
| `i64.trunc_f64_u` | `0xb1` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/addition/index.md | ---
title: Addition
slug: WebAssembly/Reference/Numeric/Addition
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`add`** instructions, are used for adding up two numbers, similar to the **`+`** operator in other languages.
{{EmbedInteractiveExample("pages/wat/add.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 10
i32.const 3
;; add up both numbers
i32.add
;; the top item on the stack will now be 13 (10 + 3 = 13)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.add` | `0x6a` |
| `i64.add` | `0x7c` |
| `f32.add` | `0x92` |
| `f64.add` | `0xa0` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/demote/index.md | ---
title: Demote
slug: WebAssembly/Reference/Numeric/Demote
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`demote`** instruction, is used to convert (demote) numbers of type `f64` to type `f32`.
{{EmbedInteractiveExample("pages/wat/demote.html", "tabbed-taller")}}
## Syntax
```wasm
;; push an f64 onto the stack
f64.const 10.5
;; demote from f64 to f32
f32.demote_f64
;; the top item on the stack will now be the value 10.5 of type f32
```
| Instruction | Binary opcode |
| ---------------- | ------------- |
| `f32.demote_f64` | `0xb6` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/min/index.md | ---
title: Min
slug: WebAssembly/Reference/Numeric/Min
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`min`** instructions, are used for getting the lower of two numbers.
{{EmbedInteractiveExample("pages/wat/min.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
f32.const 10
f32.const 3
;; get lower number
f32.min
;; the top item on the stack will now be 3
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `f32.min` | `0x96` |
| `f64.min` | `0xa4` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/left_shift/index.md | ---
title: Left shift
slug: WebAssembly/Reference/Numeric/Left_shift
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`shl`** instructions, short for _shift-left_, are used for performing a bitwise left-shift, similar to the **`<<`** operator in other languages.
{{EmbedInteractiveExample("pages/wat/shl.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 7 ;; 00000111
i32.const 1 ;; left shift one spot
;; perform a bitwise left-shift
i32.shl
;; the top item on the stack will now be 14 (00001110)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.shl` | `0x74` |
| `i64.shl` | `0x86` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/nearest/index.md | ---
title: Nearest
slug: WebAssembly/Reference/Numeric/Nearest
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`nearest`** instructions, are used for getting the value of a number rounded to the nearest integer.
{{EmbedInteractiveExample("pages/wat/nearest.html", "tabbed-standard")}}
## Syntax
```wasm
;; load a number onto the stack
f32.const -2.7
;; round to the nearest integer
f32.nearest
;; the top item on the stack will now be -3
```
| Instruction | Binary opcode |
| ------------- | ------------- |
| `f32.nearest` | `0x90` |
| `f64.nearest` | `0x9e` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/left_rotate/index.md | ---
title: Left rotate
slug: WebAssembly/Reference/Numeric/Left_rotate
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`rotl`** instructions, short for _rotate-left_, are used for performing a bitwise left-rotate.
{{EmbedInteractiveExample("pages/wat/rotl.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 3758096384 ;; 11100000_00000000_00000000_00000000
i32.const 1 ;; left rotate one spot
;; perform a bitwise left-rotate
i32.rotl
;; the top item on the stack will now be 3221225473
;; (11000000_00000000_00000000_00000001)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.rotl` | `0x77` |
| `i64.rotl` | `0x89` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/subtraction/index.md | ---
title: Subtraction
slug: WebAssembly/Reference/Numeric/Subtraction
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`sub`** instructions, short for _subtraction_, are used for subtracting one number from another number, similar to the **`-`** operator in other languages.
{{EmbedInteractiveExample("pages/wat/sub.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
i32.const 10
i32.const 3
;; subtract one number from the other
i32.sub
;; the top item on the stack will now be 7 (10 - 3 = 7)
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.sub` | `0x6b` |
| `i64.sub` | `0x7d` |
| `f32.sub` | `0x93` |
| `f64.sub` | `0xa1` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/absolute/index.md | ---
title: Absolute
slug: WebAssembly/Reference/Numeric/Absolute
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`abs`** instructions, short for _absolute_, are used to get the absolute value of a number. That is, it returns x if x is positive, and the negation of x if x is negative.
{{EmbedInteractiveExample("pages/wat/abs.html", "tabbed-standard")}}
## Syntax
```wasm
;; load a number onto the stack
f32.const -2
;; absolute
f32.abs
;; the top item on the stack will now be 2
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `f32.abs` | `0x8b` |
| `f64.abs` | `0x99` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/max/index.md | ---
title: Max
slug: WebAssembly/Reference/Numeric/Max
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`max`** instructions, are used for getting the higher of two numbers.
{{EmbedInteractiveExample("pages/wat/max.html", "tabbed-taller")}}
## Syntax
```wasm
;; load two numbers onto the stack
f32.const 10
f32.const 3
;; get higher number
f32.max
;; the top item on the stack will now be 10
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `f32.max` | `0x97` |
| `f64.max` | `0xa5` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/numeric | data/mdn-content/files/en-us/webassembly/reference/numeric/less_than/index.md | ---
title: Less than
slug: WebAssembly/Reference/Numeric/Less_than
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`lt`** instructions, short for _less than_, check if a number is less than another number. If the first number is less than the second number equal `1` will be pushed on to the stack, otherwise `0` will be pushed on to the stack.
The integer types have separate less than instructions for signed (**`lt_s`**) and unsigned (**`lt_u`**) numbers.
{{EmbedInteractiveExample("pages/wat/lt.html", "tabbed-taller")}}
## Syntax
```wasm
;; load 2 numbers on to the stack
local.get $num
i32.const 2
;; check if $num is less then '2'
i32.lt_u
;; if $num is less than the `2`, `1` will be pushed on to the stack,
;; otherwise `0` will be pushed on to the stack.
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `i32.lt_s` | `0x48` |
| `i32.lt_u` | `0x49` |
| `i64.lt_s` | `0x53` |
| `i64.lt_u` | `0x54` |
| `f32.lt` | `0x5d` |
| `f64.lt` | `0x63` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference | data/mdn-content/files/en-us/webassembly/reference/variables/index.md | ---
title: WebAssembly variable instructions
slug: WebAssembly/Reference/Variables
page-type: landing-page
---
{{WebAssemblySidebar}}
WebAssembly variable instructions.
- [`Declare local`](/en-US/docs/WebAssembly/Reference/Variables/Local)
- : Declare a new local variable.
- [`Get local`](/en-US/docs/WebAssembly/Reference/Variables/Local_get)
- : Load the value of a local variable onto the stack.
- [`Set local`](/en-US/docs/WebAssembly/Reference/Variables/Local_set)
- : Set the value of a local variable.
- [`Tee local`](/en-US/docs/WebAssembly/Reference/Variables/Local_tee)
- : Set the value of a local variable and keep the value on the stack.
- [`Declare global`](/en-US/docs/WebAssembly/Reference/Variables/Global)
- : Declare a new global variable.
- [`Get global`](/en-US/docs/WebAssembly/Reference/Variables/Global_get)
- : Load the value of a global variable onto the stack.
- [`Set global`](/en-US/docs/WebAssembly/Reference/Variables/Global_set)
- : Set the value of a global variable.
| 0 |
data/mdn-content/files/en-us/webassembly/reference/variables | data/mdn-content/files/en-us/webassembly/reference/variables/local/index.md | ---
title: Local
slug: WebAssembly/Reference/Variables/Local
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`local`** instruction declares a new local variable.
{{EmbedInteractiveExample("pages/wat/local.html", "tabbed-taller")}}
## Syntax
```wasm
;; declare new variable named $val of type i32
(local $val i32)
```
| 0 |
data/mdn-content/files/en-us/webassembly/reference/variables | data/mdn-content/files/en-us/webassembly/reference/variables/local_get/index.md | ---
title: Local get
slug: WebAssembly/Reference/Variables/Local_get
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`local.get`** instruction loads the value of a local variable onto the stack.
{{EmbedInteractiveExample("pages/wat/local.html", "tabbed-taller")}}
## Syntax
```wasm
;; load the value of a local variable onto the stack
local.get $val
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `local.get` | `0x20` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/variables | data/mdn-content/files/en-us/webassembly/reference/variables/global_get/index.md | ---
title: Global get
slug: WebAssembly/Reference/Variables/Global_get
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`global.get`** instruction loads the value of a global variable onto the stack.
{{EmbedInteractiveExample("pages/wat/global_get.html", "tabbed-standard")}}
## Syntax
```wasm
;; load the value of a global variable onto the stack
global.get $val
```
| Instruction | Binary opcode |
| ------------ | ------------- |
| `global.get` | `0x23` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/variables | data/mdn-content/files/en-us/webassembly/reference/variables/local_tee/index.md | ---
title: Local tee
slug: WebAssembly/Reference/Variables/Local_tee
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`local.tee`** instruction sets the value of a local variable and loads the value onto the stack.
The instruction is named after the T-splitter used in plumbing.
{{EmbedInteractiveExample("pages/wat/local_tee.html", "tabbed-taller")}}
## Syntax
```wasm
;; load the number 2 onto the stack
i32.const 2
;; store the number 2 in the variable $val and load it on the stack
local.tee $val
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `local.tee` | `0x22` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/variables | data/mdn-content/files/en-us/webassembly/reference/variables/global/index.md | ---
title: Global
slug: WebAssembly/Reference/Variables/Global
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`global`** instruction declares a new global variable.
{{EmbedInteractiveExample("pages/wat/global.html", "tabbed-taller")}}
## Syntax
```wasm
;; declare new variable named $val of type i32
(global $val i32)
```
| 0 |
data/mdn-content/files/en-us/webassembly/reference/variables | data/mdn-content/files/en-us/webassembly/reference/variables/global_set/index.md | ---
title: Global set
slug: WebAssembly/Reference/Variables/Global_set
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`global.set`** instruction sets the values of a global variable.
{{EmbedInteractiveExample("pages/wat/global_set.html", "tabbed-taller")}}
## Syntax
```wasm
;; load the number 2 onto the stack
i32.const 2
;; store the number 2 in the variable $val
global.set $val
```
| Instruction | Binary opcode |
| ------------ | ------------- |
| `global.set` | `0x24` |
| 0 |
data/mdn-content/files/en-us/webassembly/reference/variables | data/mdn-content/files/en-us/webassembly/reference/variables/local_set/index.md | ---
title: Local set
slug: WebAssembly/Reference/Variables/Local_set
page-type: webassembly-instruction
---
{{WebAssemblySidebar}}
The **`local.set`** instruction sets the values of a local variable.
{{EmbedInteractiveExample("pages/wat/local.html", "tabbed-taller")}}
## Syntax
```wasm
;; load the number 2 onto the stack
i32.const 2
;; store the number 2 in the variable $val
local.set $val
```
| Instruction | Binary opcode |
| ----------- | ------------- |
| `local.set` | `0x21` |
| 0 |
data/mdn-content/files/en-us/webassembly | data/mdn-content/files/en-us/webassembly/c_to_wasm/index.md | ---
title: Compiling a New C/C++ Module to WebAssembly
slug: WebAssembly/C_to_Wasm
page-type: guide
---
{{WebAssemblySidebar}}
When you've written a new code module in a language like C/C++, you can compile it into WebAssembly using a tool like [Emscripten](https://emscripten.org/). Let's look at how it works.
## Emscripten Environment Setup
First, let's set up the required development environment.
### Prerequisites
Get the Emscripten SDK, using these instructions: <https://emscripten.org/docs/getting_started/downloads.html>
## Compiling an example
With the environment set up, let's look at how to use it to compile a C example to Wasm. There are a number of options available when compiling with Emscripten, but the main two scenarios we'll cover are:
- Compiling to Wasm and creating HTML to run our code in, plus all the JavaScript "glue" code needed to run the Wasm in the web environment.
- Compiling to Wasm and just creating the JavaScript.
We will look at both below.
### Creating HTML and JavaScript
This is the simplest case we'll look at, whereby you get emscripten to generate everything you need to run your code, as WebAssembly, in the browser.
1. First we need an example to compile. Take a copy of the following simple C example, and save it in a file called `hello.c` in a new directory on your local drive:
```cpp
#include <stdio.h>
int main() {
printf("Hello World\n");
return 0;
}
```
2. Now, using the terminal window you used to enter the Emscripten compiler environment, navigate to the same directory as your `hello.c` file, and run the following command:
```bash
emcc hello.c -o hello.html
```
The options we've passed in with the command are as follows:
- `-o hello.html` — Specifies that we want Emscripten to generate an HTML page to run our code in (and a filename to use), as well as the Wasm module and the JavaScript "glue" code to compile and instantiate the Wasm so it can be used in the web environment.
At this point in your source directory you should have:
- The binary Wasm module code (`hello.wasm`)
- A JavaScript file containing glue code to translate between the native C functions, and JavaScript/Wasm (`hello.js`)
- An HTML file to load, compile, and instantiate your Wasm code, and display its output in the browser (`hello.html`)
### Running your example
Now all that remains is for you to load the resulting `hello.html` in a browser that supports WebAssembly. It is enabled by default from Firefox 52, Chrome 57, Edge 57, Opera 44.
> **Note:** If you try to open generated HTML file (`hello.html`) directly from your local hard drive (e.g. `file://your_path/hello.html`), you will end up with an error message along the lines of _`both async and sync fetching of the wasm failed`._ You need to run your HTML file through an HTTP server (`http://`) — see [How do you set up a local testing server?](/en-US/docs/Learn/Common_questions/Tools_and_setup/set_up_a_local_testing_server) for more information.
If everything has worked as planned, you should see "Hello world" output in the Emscripten console appearing on the web page, and your browser's JavaScript console. Congratulations, you've just compiled C to WebAssembly and run it in your browser!
### Using a custom HTML template
Sometimes you will want to use a custom HTML template. Let's look at how we can do this.
1. First of all, save the following C code in a file called `hello2.c`, in a new directory:
```cpp
#include <stdio.h>
int main() {
printf("Hello World\n");
return 0;
}
```
2. Search for the file `shell_minimal.html` in your emsdk repo. Copy it into a subdirectory called `html_template` inside your previous new directory.
3. Now navigate into your new directory (again, in your Emscripten compiler environment terminal window), and run the following command:
```bash
emcc -o hello2.html hello2.c -O3 --shell-file html_template/shell_minimal.html
```
The options we've passed are slightly different this time:
- We've specified `-o hello2.html`, meaning that the compiler will still output the JavaScript glue code and `.html`.
- We've specified `-O3`, which is used to optimize the code. Emcc has optimization levels like any other C compiler, including: `-O0` (no optimization), `-O1`, `-O2`, `-Os`, `-Oz`, `-Og`, and `-O3`. `-O3` is a good setting for release builds.
- We've also specified `--shell-file html_template/shell_minimal.html` — this provides the path to the HTML template you want to use to create the HTML you will run your example through.
4. Now let's run this example. The above command will have generated `hello2.html`, which will have much the same content as the template with some glue code added into load the generated Wasm, run it, etc. Open it in your browser and you'll see much the same output as the last example.
> **Note:** You could specify outputting just the JavaScript "glue" file\* rather than the full HTML by specifying a .js file instead of an HTML file in the `-o` flag, e.g. `emcc -o hello2.js hello2.c -O3`. You could then build your custom HTML completely from scratch, although this is an advanced approach; it is usually easier to use the provided HTML template.
>
> - Emscripten requires a large variety of JavaScript "glue" code to handle memory allocation, memory leaks, and a host of other problems
### Calling a custom function defined in C
If you have a function defined in your C code that you want to call as needed from JavaScript, you can do this using the Emscripten `ccall()` function, and the `EMSCRIPTEN_KEEPALIVE` declaration (which adds your functions to the exported functions list (see [Why do functions in my C/C++ source code vanish when I compile to JavaScript, and/or I get No functions to process?](https://emscripten.org/docs/getting_started/FAQ.html#why-do-functions-in-my-c-c-source-code-vanish-when-i-compile-to-javascript-and-or-i-get-no-functions-to-process))). Let's look at how this works.
1. To start with, save the following code as `hello3.c` in a new directory:
```cpp
#include <stdio.h>
#include <emscripten/emscripten.h>
int main() {
printf("Hello World\n");
return 0;
}
#ifdef __cplusplus
#define EXTERN extern "C"
#else
#define EXTERN
#endif
EXTERN EMSCRIPTEN_KEEPALIVE void myFunction(int argc, char ** argv) {
printf("MyFunction Called\n");
}
```
By default, Emscripten-generated code always just calls the `main()` function, and other functions are eliminated as dead code. Putting `EMSCRIPTEN_KEEPALIVE` before a function name stops this from happening. You also need to import the `emscripten.h` library to use `EMSCRIPTEN_KEEPALIVE`.
> **Note:** We are including the `#ifdef` blocks so that if you are trying to include this in C++ code, the example will still work. Due to C versus C++ name mangling rules, this would otherwise break, but here we are setting it so that it treats it as an external C function if you are using C++.
2. Now add `html_template/shell_minimal.html` with `\{\{{ SCRIPT }}}` as content into this new directory too, just for convenience (you'd obviously put this in a central place in your real dev environment).
3. Now let's run the compilation step again. From inside your latest directory (and while inside your Emscripten compiler environment terminal window), compile your C code with the following command. Note that we need to compile with `NO_EXIT_RUNTIME`: otherwise, when `main()` exits, the runtime would be shut down and it wouldn't be valid to call compiled code. This is necessary for proper C emulation: for example, to ensure that [`atexit()`](https://en.cppreference.com/w/c/program/atexit) functions are called.
```bash
emcc -o hello3.html hello3.c --shell-file html_template/shell_minimal.html -s NO_EXIT_RUNTIME=1 -s "EXPORTED_RUNTIME_METHODS=['ccall']"
```
4. If you load the example in your browser again, you'll see the same thing as before!
5. Now we need to run our new `myFunction()` function from JavaScript. First of all, open up your hello3.html file in a text editor.
6. Add a {{HTMLElement("button")}} element as shown below, just above the first opening `<script type='text/javascript'>` tag.
```html
<button id="mybutton">Run myFunction</button>
```
7. Now add the following code at the end of the first {{HTMLElement("script")}} element:
```js
document.getElementById("mybutton").addEventListener("click", () => {
alert("check console");
const result = Module.ccall(
"myFunction", // name of C function
null, // return type
null, // argument types
null, // arguments
);
});
```
This illustrates how `ccall()` is used to call the exported function.
## See also
- [emscripten.org](https://emscripten.org/) — learn more about Emscripten and its large variety of options.
- [Calling compiled C functions from JavaScript using ccall/cwrap](https://emscripten.org/docs/porting/connecting_cpp_and_javascript/Interacting-with-code.html#calling-compiled-c-functions-from-javascript-using-ccall-cwrap)
- [Why do functions in my C/C++ source code vanish when I compile to JavaScript, and/or I get No functions to process?](https://emscripten.org/docs/getting_started/FAQ.html#why-do-functions-in-my-c-c-source-code-vanish-when-i-compile-to-javascript-and-or-i-get-no-functions-to-process)
- [WebAssembly on Mozilla Research](https://research.mozilla.org/)
- [Compiling an Existing C Module to WebAssembly](/en-US/docs/WebAssembly/existing_C_to_Wasm)
| 0 |
data/mdn-content/files/en-us | data/mdn-content/files/en-us/mozilla/index.md | ---
title: Mozilla
slug: Mozilla
page-type: landing-page
---
{{FirefoxSidebar}}
The articles below include content about downloading and building Mozilla code. In addition, you'll find helpful articles about how the code works, how to build add-ons for Mozilla applications and the like.
{{LandingPageListSubpages}}
| 0 |
data/mdn-content/files/en-us/mozilla | data/mdn-content/files/en-us/mozilla/firefox/index.md | ---
title: Firefox
slug: Mozilla/Firefox
page-type: landing-page
---
{{FirefoxSidebar}}
[Firefox](https://www.mozilla.org/firefox/) is Mozilla's popular Web browser, available for multiple platforms including Windows, macOS, and Linux on the desktop and all Android and iOS mobile devices. With broad compatibility, the latest in Web technologies, and powerful development tools, Firefox is a great choice for both Web developers and end users.
Firefox is an open source project; much of the code is contributed by our huge community of volunteers. Here you can learn about how to contribute to the Firefox project and you will also find links to information about the construction of Firefox add-ons, using the developer tools in Firefox, and other topics.
Learn how to create add-ons for [Firefox](https://www.mozilla.org/firefox/), how to develop and build Firefox itself, and how the internals of Firefox and its subprojects work.
## Key resources
- Firefox developer guide
- : Our [developer guide](https://firefox-source-docs.mozilla.org/contributing/index.html) explains how to get Firefox source code, how to build it on Linux, macOS and Windows, how to find your way around, and how to contribute to the project.
- Firefox add-on guide
- : The [Add-on guide](/en-US/docs/Mozilla/Add-ons) provides information about developing and deploying Firefox extensions.
- Developer release notes
- : [Developer-focused release notes](/en-US/docs/Mozilla/Firefox/Releases); learn what new capabilities for both websites and add-ons arrive in each version of Firefox.
## Firefox channels
Firefox is available in five **channels**.
### Firefox Nightly
Each night we build Firefox from the latest code in [mozilla-central](https://hg.mozilla.org/mozilla-central/). These builds are for Firefox developers or those who want to try out the very latest cutting edge features while they're still under active development.
[Download Firefox Nightly](https://www.mozilla.org/firefox/channel/desktop/#nightly)
### Firefox Developer Edition
This is a version of Firefox tailored for developers. Firefox Developer Edition has all the latest developer tools that have reached beta. We also add some extra features for developers that are only available in this channel. It uses its own path and profile, so that you can run it alongside Release or Beta Firefox.
[Download Firefox Developer Edition](https://www.mozilla.org/firefox/developer/)
### Firefox Beta
Every four weeks, we take the features that are stable enough, and create a new version of Firefox Beta. Firefox Beta builds are for Firefox enthusiasts to test what's destined to become the next released Firefox version.
[Download Firefox Beta](https://www.mozilla.org/firefox/channel/#beta)
### Firefox
After stabilizing for another four weeks in Beta, we're ready to ship the new features to hundreds of millions of users in a new release version of Firefox.
[Download Firefox](https://www.mozilla.org/firefox/new/)
### Firefox Extended Support Release (ESR)
Firefox ESR is the long-term support edition of Firefox for desktop for use by organizations including schools, universities, businesses and others who need extended support for mass deployments.
[Download Firefox ESR](https://www.mozilla.org/firefox/all/#product-desktop-esr)
## Contents
{{LandingPageListSubpages}}
## See also
- [Mailing list](https://groups.google.com/a/mozilla.org/g/firefox-dev)
- [Release schedule](https://wiki.mozilla.org/Release_Management/Calendar)
| 0 |
data/mdn-content/files/en-us/mozilla/firefox | data/mdn-content/files/en-us/mozilla/firefox/experimental_features/index.md | ---
title: Experimental features in Firefox
slug: Mozilla/Firefox/Experimental_features
page-type: guide
---
{{FirefoxSidebar}}
This page lists Firefox's experimental and partially implemented features, including those for proposed or cutting-edge web platform standards, along with information on the builds in which they are present, whether or not they are activated "by default", and which _preference_ can be used to activate or deactivate them.
This allows you to test the features before they are released.
New features appear first in the [Firefox Nightly](https://www.mozilla.org/en-US/firefox/channel/desktop/) build, where they are often enabled by default.
They later propagate though to [Firefox Developer Edition](https://www.mozilla.org/en-US/firefox/developer/) and eventually to the release build.
After a feature is enabled by default in a release build, it is no longer considered experimental and should be removed from the topic.
Experimental features can be enabled or disabled using the [Firefox Configuration Editor](https://support.mozilla.org/en-US/kb/about-config-editor-firefox) (enter `about:config` in the Firefox address bar) by modifying the associated _preference_ listed below.
> **Note:** For editors - when adding features to these tables, please try to include a link to the relevant bug or bugs using `[Firefox bug <number>](https://bugzil.la/<number>)`.
## HTML
### Layout for input type="search"
Layout for `input type="search"` has been updated. This causes a search field to have a clear icon once someone starts typing in it, to match other browser implementations. (See [Firefox bug 558594](https://bugzil.la/558594) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>81</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>81</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>81</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>81</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.forms.input-type-search.enabled</code></td>
</tr>
</tbody>
</table>
### Toggle password display
HTML password input elements ([`<input type="password">`](/en-US/docs/Web/HTML/Element/input/password)) include an "eye" icon that can be toggled to display or obscure the password text ([Firefox bug 502258](https://bugzil.la/502258)).
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>96</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>96</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>96</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>96</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.forms.input-type-show-password-button.enabled</code></td>
</tr>
</tbody>
</table>
## CSS
### Hex boxes to display stray control characters
This feature renders control characters (Unicode category Cc) other than _tab_ (`U+0009`), _line feed_ (`U+000A`), _form feed_ (`U+000C`), and _carriage return_ (`U+000D`) as a hexbox when they are not expected. (See [Firefox bug 1099557](https://bugzil.la/1099557) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>43</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>43</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>43</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>43</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>layout.css.control-characters.enabled</code> or
<code>layout.css.control-characters.visible</code>
</td>
</tr>
</tbody>
</table>
### initial-letter property
The {{cssxref("initial-letter")}} CSS property is part of the [CSS Inline Layout](https://drafts.csswg.org/css-inline/) specification and allows you to specify how dropped, raised, and sunken initial letters are displayed. (See [Firefox bug 1223880](https://bugzil.la/1223880) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>50</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>50</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>50</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>50</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.initial-letter.enabled</code></td>
</tr>
</tbody>
</table>
### content-visibility: auto value
The [`content-visibility`](/en-US/docs/Web/CSS/content-visibility) CSS property value `auto` allows content to skip rendering if it is not [relevant to the user](/en-US/docs/Web/CSS/CSS_containment#relevant_to_the_user).
(See [Firefox bug 1798485](https://bugzil.la/1798485) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>113</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>109</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>109</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>109</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.content-visibility.enabled</code></td>
</tr>
</tbody>
</table>
Note:
- The related {{domxref("element/contentvisibilityautostatechange_event", "contentvisibilityautostatechange")}} event and associated {{domxref("ContentVisibilityAutoStateChangeEvent")}} interface were added in version 110, and are gated by the same preference.
These can be used by application code to monitor visibility changes and stop processes related to rendering the element when the user agent is [skipping its contents](/en-US/docs/Web/CSS/CSS_containment#skips_its_contents).
(See [Firefox bug 1791759](https://bugzil.la/1791759) for more details.)
- The {{domxref("Element.checkVisibility()")}} `options` object parameter now takes the property `contentVisibilityAuto`, which can be set `true` to test if the element has `content-visibility: auto` set and is currently skipping rendering its content (the `options` object also takes new values `opacityProperty` and `visibilityProperty` but these are not related to `content-visibility`).
(See [Firefox bug 1859852](https://bugzil.la/1859852) for more details).
### Single numbers as aspect ratio in media queries
Support for using a single {{cssxref("number")}} as a {{cssxref("ratio")}} when specifying the aspect ratio for a [media query](/en-US/docs/Web/CSS/CSS_media_queries). (See [Firefox bug 1565562](https://bugzil.la/1565562) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>70</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>70</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>70</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>70</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.aspect-ratio-number.enabled</code></td>
</tr>
</tbody>
</table>
### backdrop-filter property
The {{cssxref("backdrop-filter")}} property applies filter effects to the area behind an element. (See [Firefox bug 1178765](https://bugzil.la/1178765) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>70</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>70</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>70</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>70</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.backdrop-filter.enabled</code></td>
</tr>
</tbody>
</table>
### Masonry grid layout
Adds support for a [masonry-style layout](/en-US/docs/Web/CSS/CSS_grid_layout/Masonry_layout) based on grid layout where one axis has a masonry layout and the other has a normal grid layout. This allows developers to easily create gallery style layouts like on Pinterest. See [Firefox bug 1607954](https://bugzil.la/1607954) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>77</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>77</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>77</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>77</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>layout.css.grid-template-masonry-value.enabled</code>
</td>
</tr>
</tbody>
</table>
### fit-content() function
The {{cssxref("fit-content_function", "fit-content()")}} function as it applies to {{cssxref("width")}} and other sizing properties. This function is already well-supported for CSS Grid Layout track sizing. (See [Firefox bug 1312588](https://bugzil.la/1312588) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>91</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>91</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>91</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>91</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.fit-content-function.enabled</code></td>
</tr>
</tbody>
</table>
### Scroll-driven animations
Earlier called "scroll-linked animations", a scroll-driven animation depends on the scroll position of a scrollbar instead of time or some other dimension.
The {{cssxref('scroll-timeline-name')}} and {{cssxref('scroll-timeline-axis')}} properties (and the {{cssxref('scroll-timeline')}} shorthand property) allow you to specify that a particular scrollbar in a particular named container can be used as the source for a scroll-driven animation.
The scroll timeline can then be associated with an [animation](/en-US/docs/Web/CSS/CSS_animations) by setting the {{cssxref('animation-timeline')}} property to the name value defined using `scroll-timeline-name`.
When using the {{cssxref('scroll-timeline')}} shorthand property, the order of the property values must be {{cssxref('scroll-timeline-name')}} followed by {{cssxref('scroll-timeline-axis')}}. The longhand and shorthand properties are both available behind the preference.
You can alternatively use the [`scroll()`](/en-US/docs/Web/CSS/animation-timeline/scroll) functional notation with {{cssxref('animation-timeline')}} to indicate that a scrollbar axis in an ancestor element will be used for the timeline.
For more information, see [Firefox bug 1807685](https://bugzil.la/1807685), [Firefox bug 1804573](https://bugzil.la/1804573), [Firefox bug 1809005](https://bugzil.la/1809005), [Firefox bug 1676791](https://bugzil.la/1676791), [Firefox bug 1754897](https://bugzil.la/1754897), and [Firefox bug 1737918](https://bugzil.la/1737918).
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>110</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>110</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>110</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>110</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.scroll-driven-animations.enabled</code></td>
</tr>
</tbody>
</table>
### @font-face src feature checking
The `@font-face` [`src` descriptor](/en-US/docs/Web/CSS/@font-face/src) now supports the `tech()` function, allowing fallback of whether a font resource is downloaded based on whether the user-agent supports a particular font feature or technology.
See [Firefox bug 1715546](https://bugzil.la/1715546) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>105</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>105</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>105</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>105</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.font-tech.enabled</code></td>
</tr>
</tbody>
</table>
### font-variant-emoji
The CSS [`font-variant-emoji`](/en-US/docs/Web/CSS/font-variant-emoji) property allows you to set a default presentation style for displaying emojis.
See ([Firefox bug 1461589](https://bugzil.la/1461589)) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>108</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>108</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>108</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>108</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.font-variant-emoji.enabled</code></td>
</tr>
</tbody>
</table>
### page-orientation
The **`page-orientation`** [CSS](/en-US/docs/Web/CSS) descriptor for the {{cssxref("@page")}} at-rule controls the rotation of a printed page. It handles the flow of content across pages when the orientation of a page is changed. This behavior differs from the [`size`](/en-US/docs/Web/CSS/@page/size) descriptor in that a user can define the direction in which to rotate the page.
See ([Firefox bug 1673987](https://bugzil.la/1673987)) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>111</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>111</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>111</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>111</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.page-orientation.enabled</code></td>
</tr>
</tbody>
</table>
### prefers-reduced-transparency media feature
The CSS [`prefers-reduced-transparency`](/en-US/docs/Web/CSS/@media/prefers-reduced-transparency) media feature lets you detect if a user has enabled the setting to minimize the amount of transparent or translucent layer effects on their device.
See ([Firefox bug 1736914](https://bugzil.la/1736914)) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>113</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>113</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>113</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>113</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.prefers-reduced-transparency.enabled</code></td>
</tr>
</tbody>
</table>
### inverted-colors media feature
The CSS [`inverted-colors`](/en-US/docs/Web/CSS/@media/inverted-colors) media feature lets you detect if a user agent or the underlying operating system is inverting colors.
See ([Firefox bug 1794628](https://bugzil.la/1794628)) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.inverted-colors.enabled</code></td>
</tr>
</tbody>
</table>
### Named view progress timelines property
The CSS [`view-timeline-name`](/en-US/docs/Web/CSS/view-timeline-name) property lets you give a name to particular element, identifying that its ancestor scroller element is the source of a view progress timeline.
The name can then be assigned to the `animation-timeline`, which then animates the associated element as it moves through the visible area of its ancestor scroller.
See ([Firefox bug 1737920](https://bugzil.la/1737920)) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.scroll-driven-animations.enabled</code></td>
</tr>
</tbody>
</table>
### Anonymous view progress timelines function
The CSS [`view()`](/en-US/docs/Web/CSS/animation-timeline/view) function lets you specify that the `animation-timeline` for an element is a view progress timeline, which will animate the element as it moves through the visible area of its ancestor scroller.
The function defines the axis of the parent element that supplies the timeline, along with the inset within the visible area at which the animation starts and begins.
See ([Firefox bug 1808410](https://bugzil.la/1808410)) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.scroll-driven-animations.enabled</code></td>
</tr>
</tbody>
</table>
### zoom property
The non-standard CSS {{cssxref("zoom")}} property is enabled in the Nightly release and lets you magnify an element similar to the {{cssxref("transform")}} property, but it affects the layout size of the element.
See ([Firefox bug 1855763](https://bugzil.la/1855763) and [Firefox bug 390936](https://bugzil.la/390936)) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>120</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>120</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>120</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>120</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>layout.css.zoom.enabled</code>
</td>
</tr>
</tbody>
</table>
To ensure compatibility with these changes, the [Vendor-prefixed transform properties](#vendor-prefixed-transform-properties) and the [Vendor-prefixed transition properties](#vendor-prefixed-transition-properties) are disabled in the Nightly release.
These changes are described in the following sections.
### text-wrap: balance & stable values
The [`text-wrap`](/en-US/docs/Web/CSS/text-wrap) CSS property values `balance` and `stable` allow the layout of short content to be wrapped in a balanced manner and for editable content to not reflow while the user is editing it, respectively.
(See [Firefox bug 1731541](https://bugzil.la/1731541) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>120</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>120</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>120</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>120</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.text-wrap-balance.enabled, layout.css.text-wrap-balance.limit, layout.css.text-wrap-balance-after-clamp.enabled</code></td>
</tr>
</tbody>
</table>
#### Vendor-prefixed transform properties
The `-moz-` prefixed [CSS transform](/en-US/docs/Web/CSS/CSS_transforms) properties have been disabled in the Nightly release via the `layout.css.prefixes.transforms` preference being set to `false` ([Firefox bug 1855763](https://bugzil.la/1855763)).
Specifically, the disabled properties are:
- `-moz-backface-visibility`
- `-moz-perspective`
- `-moz-perspective-origin`
- `-moz-transform`
- `-moz-transform-origin`
- `-moz-transform-style`
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>120</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>120</td>
<td>Yes</td>
</tr>
<tr>
<th>Beta</th>
<td>120</td>
<td>Yes</td>
</tr>
<tr>
<th>Release</th>
<td>120</td>
<td>Yes</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>layout.css.prefixes.transforms</code>
</td>
</tr>
</tbody>
</table>
#### Vendor-prefixed transition properties
The `-moz-` prefixed [CSS transitions](/en-US/docs/Web/CSS/CSS_transitions) properties have been disabled in the Nightly release via the `layout.css.prefixes.transitions` preference being set to `false` ([Firefox bug 1855763](https://bugzil.la/1855763)).
Specifically, the disabled properties are:
- `-moz-transition`
- `-moz-transition-delay`
- `-moz-transition-duration`
- `-moz-transition-property`
- `-moz-transition-timing-function`
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>120</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>120</td>
<td>Yes</td>
</tr>
<tr>
<th>Beta</th>
<td>120</td>
<td>Yes</td>
</tr>
<tr>
<th>Release</th>
<td>120</td>
<td>Yes</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>layout.css.prefixes.transitions</code>
</td>
</tr>
</tbody>
</table>
## SVG
### SVGPathSeg APIs
The SVGPathSeg APIs are being unshipped, and have been placed behind a preference.
This includes: `SVGPathSegList`, [SVGPathElement.getPathSegAtLength()](/en-US/docs/Web/API/SVGPathElement), `SVGAnimatedPathData`.
(See [Firefox bug 1388931](https://bugzil.la/1388931) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version removed</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>97</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>97</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>97</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>97</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.svg.pathSeg.enabled</code></td>
</tr>
</tbody>
</table>
## JavaScript
### Intl.Segmenter
The {{jsxref("Intl.Segmenter")}} is supported in nightly builds, allowing developers to perform locale-sensitive text segmentation.
This enables splitting a string into meaningful items (graphemes, words or sentences) in different locales.
(See [Firefox bug 1423593](https://bugzil.la/1423593) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>122</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>NA</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>NA</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>NA</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">None</td>
</tr>
</tbody>
</table>
## APIs
### Graphics: Canvas, WebGL, and WebGPU
#### Hit regions
Whether the mouse coordinates are within a particular area on the canvas is a common problem to solve. The hit region API allows you to define an area of your canvas and provides another possibility to expose interactive content on a canvas to accessibility tools.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>30</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>30</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>30</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>30</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>canvas.hitregions.enabled</code></td>
</tr>
</tbody>
</table>
#### WebGL: Draft extensions
When this preference is enabled, any WebGL extensions currently in "draft" status which are being tested are enabled for use. Currently, there are no WebGL extensions being tested by Firefox.
#### WebGPU API
The [WebGPU API](/en-US/docs/Web/API/WebGPU_API) provides low-level support for performing computation and graphics rendering using the [Graphics Processing Unit](https://en.wikipedia.org/wiki/Graphics_Processing_Unit) (GPU) of the user's device or computer. See [Firefox bug 1602129](https://bugzil.la/1602129) for our progress on this API.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>113</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>73</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>73</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>73</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.webgpu.enabled</code></td>
</tr>
</tbody>
</table>
### WebRTC and media
The following experimental features include those found in the [WebRTC API](/en-US/docs/Web/API/WebRTC_API), the [Web Audio API](/en-US/docs/Web/API/Web_Audio_API), the [Media Source Extensions API](/en-US/docs/Web/API/Media_Source_Extensions_API), the [Encrypted Media Extensions API](/en-US/docs/Web/API/Encrypted_Media_Extensions_API), and the [Media Capture and Streams API](/en-US/docs/Web/API/Media_Capture_and_Streams_API).
#### Asynchronous SourceBuffer add and remove
This adds the promise-based methods {{domxref("SourceBuffer.appendBufferAsync", "appendBufferAsync()")}} and {{domxref("SourceBuffer.removeAsync", "removeAsync()")}} for adding and removing media source buffers to the {{domxref("SourceBuffer")}} interface. See [Firefox bug 1280613](https://bugzil.la/1280613) and [Firefox bug 778617](https://bugzil.la/778617) for more information.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>62</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>62</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>62</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>62</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>media.mediasource.experimental.enabled</code></td>
</tr>
</tbody>
</table>
#### AVIF compliance strictness
The `image.avif.compliance_strictness` preference can be used to control the _strictness_ applied when processing [AVIF](/en-US/docs/Web/Media/Formats/Image_types#avif_image) images.
This allows Firefox users to display images that render on some other browsers, even if they are not strictly compliant.
Permitted values are:
- `0`: Accept images with specification violations in both recommendations ("should" language) and requirements ("shall" language), provided they can be safely or unambiguously interpreted.
- `1` (default): Reject violations of requirements, but allow violations of recommendations.
- `2`: Strict. Reject any violations in requirements or recommendations.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Default value</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>92</td>
<td>1</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>92</td>
<td>1</td>
</tr>
<tr>
<th>Beta</th>
<td>92</td>
<td>1</td>
</tr>
<tr>
<th>Release</th>
<td>92</td>
<td>1</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>image.avif.compliance_strictness</code></td>
</tr>
</tbody>
</table>
#### JPEG XL support
Firefox supports [JPEG XL](https://jpeg.org/jpegxl/) images if this feature is enabled.
See [Firefox bug 1539075](https://bugzil.la/1539075) for more details.
Note that, as shown below, the feature is only available on Nightly builds (irrespective of whether the preference is set).
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>90</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>—</td>
<td>—</td>
</tr>
<tr>
<th>Beta</th>
<td>—</td>
<td>—</td>
</tr>
<tr>
<th>Release</th>
<td>—</td>
<td>—</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>image.jxl.enabled</code></td>
</tr>
</tbody>
</table>
#### OpenFont COLRv1 fonts
This feature provides support for the [OpenFont COLRv1 font specification](https://docs.microsoft.com/en-us/typography/opentype/spec/).
This enables compression-friendly color vector fonts with gradients, compositing and blending to be loaded using the CSS [`@font-face`](/en-US/docs/Web/CSS/@font-face) rule, or the [CSS Font Loading API](/en-US/docs/Web/API/CSS_Font_Loading_API).
See [Firefox bug 1740530](https://bugzil.la/1740530) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>105</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>105</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>105</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>105</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>gfx.font_rendering.colr_v1.enabled</code></td>
</tr>
</tbody>
</table>
#### CSS Properties and Values API
The [CSS Properties and Values API](/en-US/docs/Web/API/CSS_Properties_and_Values_API) allows developers to register custom CSS properties through JavaScript via [`registerProperty()`](/en-US/docs/Web/API/CSS/registerProperty_static) or in CSS using the [`@property`](/en-US/docs/Web/CSS/@property) at-rule.
Registering properties using these two methods allows for type checking, default values, and properties that do or do not inherit values from their parent elements.
See [Firefox bug 1840480](https://bugzil.la/1840480) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>116</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>116</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>116</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>116</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.property-and-value-api.enabled</code></td>
</tr>
</tbody>
</table>
#### CSS Custom Highlight API
The [CSS Custom Highlight API](/en-US/docs/Web/API/CSS_Custom_Highlight_API) provides a mechanism for styling arbitrary text ranges in a document (generalizing the behavior of other highlight pseudo-elements such as {{cssxref('::selection')}}, {{cssxref('::spelling-error')}}, {{cssxref('::grammar-error')}}, and {{cssxref('::target-text')}}).
The ranges are defined in JavaScript using [`Range`](/en-US/docs/Web/API/Range) instances grouped in a [`Highlight`](/en-US/docs/Web/API/Highlight), and then registered with a name using [`HighlightRegistry`](/en-US/docs/Web/API/HighlightRegistry).
The CSS [`::highlight`](/en-US/docs/Web/CSS/::highlight) pseudo-element is used to apply styles to a registered highlight.
See [Firefox bug 1703961](https://bugzil.la/1703961) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>117</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>117</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>117</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>117</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.customHighlightAPI.enabled</code></td>
</tr>
</tbody>
</table>
### Service Workers
#### Preloading of service worker resources on navigation
The {{domxref("NavigationPreloadManager")}} interface can be used to enable preloading of resources when navigating to a page.
Preloading occurs in parallel with worker bootup, reducing the total time from start of navigation until resources are fetched.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>99</td>
<td>yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>97</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>97</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>97</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.serviceWorkers.navigationPreload.enabled</code></td>
</tr>
</tbody>
</table>
### WebVR API
#### WebVR API (Disabled)
The deprecated [WebVR API](/en-US/docs/Web/API/WebVR_API) is on the path for removal.
It is disabled by default on all builds [Firefox bug 1750902](https://bugzil.la/1750902).
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version removed</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>98</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>98</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>98</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>98</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.vr.enabled</code></td>
</tr>
</tbody>
</table>
### HTML DOM API
#### Shadow DOM
Firefox now supports the `clonable` option and property for shadow DOM.
- The {{domxref("Element.attachShadow()")}} method's `clonable` boolean option specifies whether the created shadow root is clonable: the default value is `false` but when set to `true`, the shadow host cloned with {{domxref("Node.cloneNode()")}} or {{domxref("Document.importNode()")}} will include shadow root in the copy.
- The {{domxref("ShadowRoot")}} interface's {{domxref("ShadowRoot.clonable", "clonable")}} read-only property returns `true` if the shadow root is clonable, and `false` otherwise.
When shadow root is created via declarative shadow DOM, the `clonable` option is set to `true` by default, and the `clonable` property returns `true`. ([Firefox bug 1868428](https://bugzil.la/1868428))
| Release channel | Version added | Enabled by default? |
| ----------------- | ------------- | ------------------- |
| Nightly | 122 | Yes |
| Developer Edition | NA | No |
| Beta | NA | No |
| Release | NA | No |
#### Popover API
Firefox now supports the [Popover API](/en-US/docs/Web/API/Popover_API).
The following Web APIs are now implemented:
- [`HTMLButtonElement.popoverTargetElement`](/en-US/docs/Web/API/HTMLButtonElement/popoverTargetElement) and [`HTMLButtonElement.popoverTargetAction`](/en-US/docs/Web/API/HTMLButtonElement/popoverTargetAction).
- [`HTMLInputElement.popoverTargetElement`](/en-US/docs/Web/API/HTMLInputElement/popoverTargetElement) and [`HTMLInputElement.popoverTargetAction`](/en-US/docs/Web/API/HTMLInputElement/popoverTargetAction).
- [`HTMLElement.popover`](/en-US/docs/Web/API/HTMLElement/popover), [`HTMLElement.hidePopover()`](/en-US/docs/Web/API/HTMLElement/hidePopover), [`HTMLElement.showPopover()`](/en-US/docs/Web/API/HTMLElement/showPopover), and [`HTMLElement.togglePopover()`](/en-US/docs/Web/API/HTMLElement/togglePopover).
- `HTMLElement` [`beforetoggle` event](/en-US/docs/Web/API/HTMLElement/beforetoggle_event), `HTMLElement` [`toggle_event` event](/en-US/docs/Web/API/HTMLElement/toggle_event), and [`ToggleEvent`](/en-US/docs/Web/API/ToggleEvent).
CSS updates include:
- [`:popover-open`](/en-US/docs/Web/CSS/:popover-open)
- [`::backdrop`](/en-US/docs/Web/CSS/::backdrop) has been extended to support popovers
The following HTML global attributes are supported:
- [`popovertarget`](/en-US/docs/Web/HTML/Element/button#popovertarget)
- [`popovertargetaction`](/en-US/docs/Web/HTML/Element/button#popovertargetaction)
See [Firefox bug 1823757](https://bugzil.la/1823757) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>122</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>114</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.element.popover.enabled</code></td>
</tr>
</tbody>
</table>
#### HTMLMediaElement method: setSinkId()
{{domxref("HTMLMediaElement.setSinkId()")}} allows you to set the sink ID of an audio output device on an {{domxref("HTMLMediaElement")}}, thereby changing where the audio is being output. See [Firefox bug 934425](https://bugzil.la/934425) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>64</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>64</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>64</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>64</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>media.setsinkid.enabled</code></td>
</tr>
</tbody>
</table>
#### HTMLMediaElement properties: audioTracks and videoTracks
Enabling this feature adds the {{domxref("HTMLMediaElement.audioTracks")}} and {{domxref("HTMLMediaElement.videoTracks")}} properties to all HTML media elements. However, because Firefox doesn't currently support multiple audio and video tracks, the most common use cases for these properties don't work, so they're both disabled by default. See [Firefox bug 1057233](https://bugzil.la/1057233) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>33</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>33</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>33</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>33</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>media.track.enabled</code></td>
</tr>
</tbody>
</table>
#### ClipboardItem
The {{domxref('ClipboardItem')}} interface of the {{domxref('Clipboard API')}} is now supported. It is available in nightly or early beta builds.
(See [Firefox bug 1809106](https://bugzil.la/1809106) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>122</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>87</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>122</td>
<td>Yes</td>
</tr>
<tr>
<th>Release</th>
<td>87</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.events.asyncClipboard.clipboardItem</code></td>
</tr>
</tbody>
</table>
#### Clipboard read and write
The [Clipboard.read()](/en-US/docs/Web/API/Clipboard/read), [Clipboard.readText()](/en-US/docs/Web/API/Clipboard/readText), and [Clipboard.write()](/en-US/docs/Web/API/Clipboard/write) methods of the {{domxref('Clipboard')}} interface are now available in nightly and early beta builds
(See [Firefox bug 1809106](https://bugzil.la/1809106) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>122</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>90</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>Yes</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>90</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.events.asyncClipboard.readText</code> and <code>dom.events.asyncClipboard.clipboardItem</code></td>
</tr>
</tbody>
</table>
#### HTML Sanitizer API
The {{domxref('HTML Sanitizer API')}} allow developers to take untrusted strings of HTML and sanitize them for safe insertion into a document's DOM. Default elements within each configuration property (those to be sanitized) are still under consideration. Due to this the config parameter has not been implemented (see {{domxref('Sanitizer.sanitizer()', 'the constructor')}} for more information). See [Firefox bug 1673309](https://bugzil.la/1673309) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>84</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>84</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>84</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>84</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.security.sanitizer.enabled</code></td>
</tr>
</tbody>
</table>
#### GeometryUtils methods: convertPointFromNode(), convertRectFromNode(), and convertQuadFromNode()
The `GeometryUtils` methods `convertPointFromNode()`, `convertRectFromNode()`, and `convertQuadFromNode()` map the given point, rectangle, or quadruple from the {{domxref("Node")}} on which they're called to another node. (See [Firefox bug 918189](https://bugzil.la/918189) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>31</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>31</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>31</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>31</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.convertFromNode.enable</code></td>
</tr>
</tbody>
</table>
#### GeometryUtils method: getBoxQuads()
The `GeometryUtils` method `getBoxQuads()` returns the CSS boxes for a {{domxref("Node")}} relative to any other node or viewport. (See [Firefox bug 917755](https://bugzil.la/917755) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>31</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>31</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>31</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>31</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>layout.css.getBoxQuads.enabled</code></td>
</tr>
</tbody>
</table>
#### CustomStateSet and the :state() pseudo-class: States for custom elements
You can now define custom states for custom elements and match them using CSS.
Custom states are represented as custom identifiers that can be added to, or removed from, the element's {{domxref("ElementInternals.states")}} property (a {{domxref("CustomStateSet")}}). The CSS [`:state()`](/en-US/docs/Web/CSS/:state) pseudo-class takes a custom identifier as an argument and matches the custom elements if the identifier is present in their set of states.
(See [Firefox bug 1861466](https://bugzil.la/1861466) and [Firefox bug 1866351](https://bugzil.la/1866351) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>121</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>121</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>121</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>121</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.element.customstateset.enabled</code></td>
</tr>
</tbody>
</table>
### Payment Request API
#### Primary payment handling
The [Payment Request API](/en-US/docs/Web/API/Payment_Request_API) provides support for handling web-based payments within web content or apps. Due to a bug that came up during testing of the user interface, we have decided to postpone shipping this API while discussions over potential changes to the API are held. Work is ongoing. (See [Firefox bug 1318984](https://bugzil.la/1318984) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>55</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>55</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>55</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>55</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>dom.payments.request.enabled</code> and<br /><code
>dom.payments.request.supportedRegions</code
>
</td>
</tr>
</tbody>
</table>
### WebShare API
The [Web Share API](/en-US/docs/Web/API/Web_Share_API) allows sharing of files, URLs and other data from a site.
This feature is enabled on Android in all builds, but behind a preference on Desktop (unless specified below).
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version changed</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>71</td>
<td>No (default). Yes (Windows from version 92)</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>71</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>71</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>71</td>
<td>No (Desktop). Yes (Android).</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.webshare.enabled</code></td>
</tr>
</tbody>
</table>
### Screen Orientation API
#### ScreenOrientation.lock()
The {{domxref("ScreenOrientation.lock()")}} method allows a device to be locked to a particular orientation, if supported by the device and allowed by browser pre-lock requirements.
Typically locking the orientation is only allowed on mobile devices when the document is being displayed full screen.
See [Firefox bug 1697647](https://bugzil.la/1697647) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version changed</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>111</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>97</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>97</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>97</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.screenorientation.allow-lock</code></td>
</tr>
</tbody>
</table>
### Screen Wake Lock API
The [Screen Wake Lock API](/en-US/docs/Web/API/Screen_Wake_Lock_API) allows a web application to request that the screen not be dimmed or locked while it is active.
This is useful for navigation and reading applications, and any application where the screen doesn't get regular tactile input while the application is in use (the default way to keep a screen awake).
The API is accessed through {{domxref("Navigator.wakeLock")}} in secure contexts, which returns a {{domxref("WakeLock")}}.
This can be used to request a {{domxref("WakeLockSentinel")}} that can be used to monitor the status of the wake lock, and release it manually.
See [Firefox bug 1589554](https://bugzil.la/1589554) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version changed</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>122</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>122</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>122</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>122</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.screenwakelock.enabled</code></td>
</tr>
</tbody>
</table>
### Prioritized Task Scheduling API
The [Prioritized Task Scheduling API](/en-US/docs/Web/API/Prioritized_Task_Scheduling_API) provides a standardized way to prioritize all tasks belonging to an application, whether they defined in a website developer's code, or in third party libraries and frameworks.
This is enabled on Firefox Nightly (only) from Firefox 101.
No preference is provided to allow it to be enabled in other releases.
### Notifications API
Notifications have the [`requireInteraction`](/en-US/docs/Web/API/Notification/requireInteraction) property set to true by default on Windows systems and in the Nightly release ([Firefox bug 1794475](https://bugzil.la/1794475)).
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version changed</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>117</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>117</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>117</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>117</td>
<td>Windows only</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.webnotifications.requireinteraction.enabled</code></td>
</tr>
</tbody>
</table>
### Web Codecs API
The [Web Codecs API](/en-US/docs/Web/API/WebCodecs_API) gives web developers low-level access to the individual frames of a video stream and chunks of audio.
The following interfaces are supported (on Linux desktop only): [`VideoEncoder`](/en-US/docs/Web/API/VideoEncoder), [`VideoDecoder`](/en-US/docs/Web/API/VideoDecoder), [`EncodedVideoChunk`](/en-US/docs/Web/API/EncodedVideoChunk), [`VideoFrame`](/en-US/docs/Web/API/VideoFrame), [`VideoColorSpace`](/en-US/docs/Web/API/VideoColorSpace).
([Firefox bug 1874445](https://bugzil.la/1874445)).
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version changed</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>123</td>
<td>Yes. Linux desktop only.</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>123</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>123</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>123</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>dom.media.webcodecs.enabled</code></td>
</tr>
</tbody>
</table>
## Security and privacy
### Block plain text requests from Flash on encrypted pages
In order to help mitigate man-in-the-middle (MitM) attacks caused by Flash content on encrypted pages, a preference has been added to treat `OBJECT_SUBREQUEST`s as active content. See [Firefox bug 1190623](https://bugzil.la/1190623) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>59</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>59</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>59</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>59</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>security.mixed_content.block_object_subrequest</code>
</td>
</tr>
</tbody>
</table>
### Insecure page labeling
These two preferences add a "Not secure" text label in the address bar next to the traditional lock icon when a page is loaded insecurely (that is, using {{Glossary("HTTP")}} rather than {{Glossary("HTTPS")}}). See [Firefox bug 1335970](https://bugzil.la/1335970) for more details.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>60</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>60</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>60</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>60</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>security.insecure_connection_text.enabled</code> for normal
browsing mode;
<code>security.insecure_connection_text.pbmode.enabled</code> for
private browsing mode
</td>
</tr>
</tbody>
</table>
### Upgrading mixed display content
When enabled, this preference causes Firefox to automatically upgrade requests for media content from HTTP to HTTPS on secure pages. The intent is to prevent mixed-content conditions in which some content is loaded securely while other content is insecure. If the upgrade fails (because the media's host doesn't support HTTPS), the media is not loaded. (See [Firefox bug 1435733](https://bugzil.la/1435733) for more details.)
This also changes the console warning; if the upgrade succeeds, the message indicates that the request was upgraded, instead of showing a warning.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>84</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>60</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>60</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>60</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>security.mixed_content.upgrade_display_content</code>
</td>
</tr>
</tbody>
</table>
### Permissions Policy / Feature policy
[Permissions Policy](/en-US/docs/Web/HTTP/Permissions_Policy) allows web developers to selectively enable, disable, and modify the behavior of certain features and APIs in the browser. It is similar to CSP but controls features instead of security behavior.
This is implemented in Firefox as **Feature Policy**, the name used in an earlier version of the specification.
Note that supported policies can be set through the [`allow`](/en-US/docs/Web/HTML/Element/iframe#allow) attribute on `<iframe>` elements even if the user preference is not set.
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>65</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>65</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>65</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>65</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>dom.security.featurePolicy.header.enabled</code>
</td>
</tr>
</tbody>
</table>
### Clear-Site-Data "cache" directive
The [`Clear-Site-Data`](/en-US/docs/Web/HTTP/Headers/Clear-Site-Data) HTTP response header `cache` directive clears the browser cache for the requesting website.
> **Note:** This was originally enabled by default, but put behind a preference in version 94 ([Firefox bug 1729291](https://bugzil.la/1729291)).
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>63</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>63</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>63</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>63</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>privacy.clearsitedata.cache.enabled</code>
</td>
</tr>
</tbody>
</table>
## HTTP
### SameSite=Lax by default
[`SameSite` cookies](/en-US/docs/Web/HTTP/Headers/Set-Cookie#samesitesamesite-value) have a default value of `Lax`.
With this setting, cookies are only sent when a user is navigating to the origin site, not for cross-site subrequests to load images or frames into a third party site and so on.
For more details see [Firefox bug 1617609](https://bugzil.la/1617609).
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>69</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>69</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>69</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>69</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>network.cookie.sameSite.laxByDefault</code></td>
</tr>
</tbody>
</table>
### Access-Control-Allow-Headers wildcard does not cover Authorization
The [`Access-Control-Allow-Headers`](/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Headers) is a response header to a [CORS preflight request](/en-US/docs/Glossary/Preflight_request), that indicates which request headers may be included in the final request.
The response directive can contain a wildcard (`*`), which indicates that the final request may include all headers except the `Authorization` header.
By default, Firefox includes the `Authorization` header in the final request after receiving a response with `Access-Control-Allow-Headers: *`.
Set the preference to `false` to ensure Firefox does not include the `Authorization` header.
For more details see [Firefox bug 1687364](https://bugzil.la/1687364).
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>115</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>115</td>
<td>Yes</td>
</tr>
<tr>
<th>Beta</th>
<td>115</td>
<td>Yes</td>
</tr>
<tr>
<th>Release</th>
<td>115</td>
<td>Yes</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>network.cors_preflight.authorization_covered_by_wildcard</code></td>
</tr>
</tbody>
</table>
## Developer tools
Mozilla's developer tools are constantly evolving. We experiment with new ideas, add new features, and test them on the Nightly and Developer Edition channels before letting them go through to beta and release. The features below are the current crop of experimental developer tool features.
### Execution context selector
This feature displays a button on the console's command line that lets you change the context in which the expression you enter will be executed. (See [Firefox bug 1605154](https://bugzil.la/1605154) and [Firefox bug 1605153](https://bugzil.la/1605153) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>75</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>75</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>75</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>75</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2"><code>devtools.webconsole.input.context</code></td>
</tr>
</tbody>
</table>
### Mobile gesture support in Responsive Design Mode
Mouse gestures are used to simulate mobile gestures like swiping/scrolling, double-tap and pinch-zooming and long-press to select/open the context menu. (See [Firefox bug 1621781](https://bugzil.la/1621781), [Firefox bug 1245183](https://bugzil.la/1245183), and [Firefox bug 1401304](https://bugzil.la/1401304) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>76<sup>[1]</sup></td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>76<sup>[1]</sup></td>
<td>Yes</td>
</tr>
<tr>
<th>Beta</th>
<td>76<sup>[1]</sup></td>
<td>Yes</td>
</tr>
<tr>
<th>Release</th>
<td>76<sup>[1]</sup></td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">n/a</td>
</tr>
</tbody>
</table>
\[1] Support for zooming using the double-tap gesture was added in Firefox 76. The other gestures were added for Firefox 79.
### Server-sent events in Network Monitor
The Network Monitor displays information for [server-sent](/en-US/docs/Web/API/Server-sent_events) events. (See [Firefox bug 1405706](https://bugzil.la/1405706) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>80</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>80</td>
<td>Yes</td>
</tr>
<tr>
<th>Beta</th>
<td>80</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>80</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>devtools.netmonitor.features.serverSentEvents</code>
</td>
</tr>
</tbody>
</table>
### CSS browser compatibility tooltips
The CSS Rules View can display browser compatibility tooltips next to any CSS properties that have known issues. For more information see: [Examine and edit HTML > Browser Compat Warnings](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_css/index.html#browser-compat-warnings).
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>81</td>
<td>No</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>81</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>81</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>81</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code
>devtools.inspector.ruleview.inline-compatibility-warning.enabled</code
>
</td>
</tr>
</tbody>
</table>
## UI
### Desktop zooming
This feature lets you enable smooth pinch zooming on desktop computers without requiring layout reflows, just like mobile devices do. (See [Firefox bug 1245183](https://bugzil.la/1245183) and [Firefox bug 1620055](https://bugzil.la/1620055) for more details.)
<table>
<thead>
<tr>
<th>Release channel</th>
<th>Version added</th>
<th>Enabled by default?</th>
</tr>
</thead>
<tbody>
<tr>
<th>Nightly</th>
<td>42</td>
<td>Yes</td>
</tr>
<tr>
<th>Developer Edition</th>
<td>42</td>
<td>No</td>
</tr>
<tr>
<th>Beta</th>
<td>42</td>
<td>No</td>
</tr>
<tr>
<th>Release</th>
<td>42</td>
<td>No</td>
</tr>
<tr>
<th>Preference name</th>
<td colspan="2">
<code>apz.allow_zooming</code> and (on Windows)
<code>apz.windows.use_direct_manipulation</code>
</td>
</tr>
</tbody>
</table>
## See also
- [Firefox developer release notes](/en-US/docs/Mozilla/Firefox/Releases)
- [Firefox Nightly](https://www.mozilla.org/en-US/firefox/channel/desktop/)
- [Firefox Developer Edition](https://www.mozilla.org/en-US/firefox/developer/)
| 0 |
data/mdn-content/files/en-us/mozilla/firefox | data/mdn-content/files/en-us/mozilla/firefox/releases/index.md | ---
title: Firefox release notes for developers
slug: Mozilla/Firefox/Releases
page-type: landing-page
---
{{FirefoxSidebar}}
Below you'll find links to the developer release notes for every Firefox release. These lovingly-crafted notes provide details on what features and APIs were added and improved and what bugs were eliminated in each version of Firefox. All written to give developers like you the information they need most. You're welcome.
{{ListSubpages("",1,1,1)}}
Whew! That's a lot of Firefoxen!
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/90/index.md | ---
title: Firefox 90 for developers
slug: Mozilla/Firefox/Releases/90
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 90 that will affect developers. Firefox 90 was released on July 13th, 2021.
> **Note:** See also [Getting lively with Firefox 90](https://hacks.mozilla.org/2021/07/getting-lively-with-firefox-90/) on Mozilla Hacks.
## Changes for web developers
### Developer Tools
- The response view now shows a [preview for web fonts](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_details/index.html#response-tab) ([Firefox bug 872078](https://bugzil.la/872078)).
### HTML
- A fix to the way that form payloads are handled around newline normalization and escaping in multipart/formdata. This meets the updated specification, and matches other browser implementations. ([Firefox bug 1686765](https://bugzil.la/1686765)).
- Firefox now sets an image's {{Glossary("intrinsic size")}} and resolution based on {{Glossary("EXIF")}} information (if present and self-consistent). This allows a server to, for example, send a low-quality placeholder image to speed up loading. It also enables a [number of other use cases](https://github.com/eeeps/exif-intrinsic-sizing-explainer) ([Firefox bug 1680387](https://bugzil.la/1680387)).
### CSS
- `-webkit-image-set()` has been implemented as an alias of the standard {{cssxref("image/image-set", "image/image-set()")}} function ([Firefox bug 1709415](https://bugzil.la/1709415)).
### JavaScript
- [Private class static and instance fields and methods](/en-US/docs/Web/JavaScript/Reference/Classes/Private_properties) are now supported by default ([Firefox bug 1708235](https://bugzil.la/1708235) and [Firefox bug 1708236](https://bugzil.la/1708236)).
- The [`in`](/en-US/docs/Web/JavaScript/Reference/Operators/in) operator can now be used to [check if a class private method or field has been defined](/en-US/docs/Web/JavaScript/Reference/Operators/in#using_the_in_operator_to_implement_branded_checks). This offers a more compact approach for handling potentially undefined features, as oppose to wrapping code in `try/catch` blocks ([Firefox bug 1648090](https://bugzil.la/1648090)).
- Custom date/time formats specified as options to the [`Intl.DateTimeFormat()` constructor](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/DateTimeFormat) can now include `dayPeriod` — a value indicating that the approximate time of day (e.g. "in the morning", "at night", etc.) should be included as a `narrow`, `short`, or `long` string ([Firefox bug 1645115](https://bugzil.la/1645115)).
- The relative indexing method `at()` has been added to the [`Array`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array), [`String`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/String) and [`TypedArray`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray) global objects. ([Firefox bug 1681371](https://bugzil.la/1681371))
### HTTP
- The HTTP {{Glossary("Fetch metadata request header", "fetch metadata request headers")}} (`Sec-Fetch-*`) are now supported. These headers provide servers with additional context about requests, including whether they are same-origin, cross-origin, same-site, or user-initiated, and where/how the requested data is to be used. This allows servers to mitigate against several types of cross-origin attacks ([Firefox bug 1695911](https://bugzil.la/1695911)).
#### Removals
- FTP has now been removed from Firefox ([Firefox bug 1574475](https://bugzil.la/1574475)). This follows [deprecation in Firefox 88](/en-US/docs/Mozilla/Firefox/Releases/88#http). Note that web extensions can still register themselves as [FTP protocol handlers](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/protocol_handlers).
### APIs
#### DOM
- Support was added for the deprecated {{DOMxref("WheelEvent")}} properties: `WheelEvent.wheelDelta`, `WheelEvent.wheelDeltaX`, and `WheelEvent.wheelDeltaY`. This allows Firefox to work with a small subset of pages that were broken by recent compatibility improvements to `WheelEvent` ([Firefox bug 1708829](https://bugzil.la/1708829)).
- The {{domxref("CanvasRenderingContext2D")}} interface of the {{domxref("Canvas API")}} now provides a {{domxref('CanvasRenderingContext2D.createConicGradient()','createConicGradient()')}} method. This returns a {{domxref('CanvasGradient')}} much like the existing {{domxref('CanvasRenderingContext2D.createLinearGradient()','linear')}} and {{domxref('CanvasRenderingContext2D.createRadialGradient()','radial')}} gradients, but allows a gradient to move around a point defined by coordinates. See [Firefox bug 1627014](https://bugzil.la/1627014) for more details.
- Support for the `matrix` protocol has been added and can now be passed into the {{domxref('Navigator.registerProtocolHandler()')}} method as a valid scheme.
### WebDriver conformance (Marionette)
- Marionette now restricts to a single active WebDriver session ([Firefox bug 1691047](https://bugzil.la/1691047)).
- Added support for the new type of user prompts in Firefox ([Firefox bug 1686741](https://bugzil.la/1686741))
- Window handles make use of a unique id now, and don't change for process
swaps as caused by [cross-group navigations](https://firefox-source-docs.mozilla.org/dom/navigation/nav_replace.html#cross-group-navigations) ([Firefox bug 1680479](https://bugzil.la/1680479)).
- Fixed an inappropriate abortion of the current WebDriver command when a
new user prompt was opened in a background tab ([Firefox bug 1701686](https://bugzil.la/1701686)).
- Fixed the `WebDriver:GetWindowHandles` command to now correctly
handle unloaded tabs ([Firefox bug 1682062](https://bugzil.la/1682062)).
- Fixed the `WebDriver:NewSession` command to always return the
`proxy` capability even if empty ([Firefox bug 1710935](https://bugzil.la/1710935)).
#### Removals
- With the [removal of the FTP support in Firefox 90](#removals_http)
the `ftpProxy` capability is no longer evaluated, and when used will
throw an `invalid argument` error ([Firefox bug 1703805](https://bugzil.la/1703805)).
## Changes for add-on developers
- The `matrix` URI scheme is now supported and can be defined as a protocol within the [`protocol_handlers`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/protocol_handlers) key in an extensions [`manifest.json`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json)
- Starting with this version, the [Cache API](/en-US/docs/Web/API/Cache) can be used in the extension pages and worker globals. For more details, see ([Firefox bug 1575625](https://bugzil.la/1575625)).
## Older versions
{{Firefox_for_developers(89)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/108/index.md | ---
title: Firefox 108 for developers
slug: Mozilla/Firefox/Releases/108
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 108 that will affect developers. Firefox 108 was released on December 13, 2022.
## Changes for web developers
### HTML
- The {{HTMLElement("source")}} element supports [`height`](/en-US/docs/Web/HTML/Element/source#height) & [`width`](/en-US/docs/Web/HTML/Element/source#width) attributes when it is a child of a {{HTMLElement("picture")}} element.
This functionality can be configured via the `dom.picture_source_dimension_attributes.enabled` preference which is now set to `true` by default ([Firefox bug 1795953](https://bugzil.la/1795953)).
### CSS
- [Trigonometric functions](/en-US/docs/Web/CSS/CSS_Functions#trigonometric_functions) are now enabled with the `layout.css.trig.enabled` preference set to `true` by default.
This allows the use of `sin()`, `cos()`, `tan()`, `asin()`, `acos()`, `atan()`, and `atan2()` functions ([Firefox bug 1774589](https://bugzil.la/1774589), [Firefox bug 1787070](https://bugzil.la/1787070)).
- CSS [`<calc-constant>`](/en-US/docs/Web/CSS/calc-constant) type is implemented to allow for well-known constants such as `pi` and `e` within [math functions](/en-US/docs/Web/CSS/CSS_Functions#math_functions) ([Firefox bug 1682444](https://bugzil.la/1682444), [Firefox bug 1787070](https://bugzil.la/1787070)).
- Container query length units are now supported via the `layout.css.container-queries.enabled` preference, which is set to `false` by default.
Setting this preference to `true` allows the use of `cqw`, `cqh`, `cqi`, `cqb`, `cqmin`, and `cqmax` units of length which are relative to the size of a query container.
For more information on these units, see the [CSS Container Queries](/en-US/docs/Web/CSS/CSS_containment/Container_queries#container_query_length_units) documentation ([Firefox bug 1744231](https://bugzil.la/1744231)).
- The [`font-variant-emoji`](/en-US/docs/Web/CSS/font-variant-emoji) property is now supported via the `layout.css.font-variant-emoji.enabled` preference, which is set to `false` by default. This property allows you to set a default presentation style for displaying emojis ([Firefox bug 1461589](https://bugzil.la/1461589)).
### JavaScript
No notable changes
### HTTP
- [`Content-Security-Policy`](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy) HTTP header directives [`style-src-elem`](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/style-src-elem) and [`style-src-attr`](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/style-src-attr) are now supported.
A server can use these to specify valid sources for stylesheet `<style>` elements and `<link>` elements with `rel="stylesheet"`, and for styles applied to individual elements, respectively ([Firefox bug 1529338](https://bugzil.la/1529338)).
- [`Content-Security-Policy`](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy) HTTP header directives [`script-src-elem`](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src-elem) and [`script-src-attr`](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src-attr) are now supported.
A server can use these to specify valid sources for JavaScript `<script>` elements, and for inline script event handlers like `onclick`, respectively ([Firefox bug 1529337](https://bugzil.la/1529337)).
- [`Content-Security-Policy`](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy) violation reports now include `effective-directive` and `status-code` properties.
For more information, see [Violation report syntax](/en-US/docs/Web/HTTP/CSP#violation_report_syntax) ([Firefox bug 1192684](https://bugzil.la/1192684)).
### APIs
- [Import maps](/en-US/docs/Web/HTML/Element/script/type/importmap) are now supported.
Import maps provide flexibility and additional control over how browsers resolve module specifiers when importing [JavaScript modules](/en-US/docs/Web/JavaScript/Guide/Modules).
([Firefox bug 1795647](https://bugzil.la/1795647)).
#### Media, WebRTC, and Web Audio
- The [Web MIDI API](/en-US/docs/Web/API/Web_MIDI_API) is now available in [secure contexts](/en-US/docs/Web/Security/Secure_Contexts).
Calls to [`navigator.requestMIDIAccess()`](/en-US/docs/Web/API/Navigator/requestMIDIAccess) will prompt users with active MIDI devices to install a [Site Permission Add-On](https://support.mozilla.org/en-US/kb/site-permission-add-ons), which is required to enable the API.
For more information see [Firefox bug 1795025](https://bugzil.la/1795025).
### WebDriver conformance (WebDriver BiDi, Marionette)
#### WebDriver BiDi
- Following a [change in the specification](https://github.com/w3c/webdriver-bidi/pull/259), log entry level `"warning"` was renamed to `"warn"` ([Firefox bug 1797115](https://bugzil.la/1797115)).
- When using `script.evaluate` and `script.callFunction` with a sandbox name equal to an empty string, the evaluation will now be done using the default realm ([Firefox bug 1793589](https://bugzil.la/1793589)).
- Added support for the `browsingContext.domContentLoaded` event ([Firefox bug 1756610](https://bugzil.la/1756610)).
#### Marionette
- Added support for the `tiltX`, `tiltY` and `twist` properties of pointer actions for `WebDriver:PerformActions` ([Firefox bug 1793832](https://bugzil.la/1793832)).
- Fixed a bug where `WebDriver:GetElementText` wasn't returning the element text for pretty-printed XML ([Firefox bug 1794099](https://bugzil.la/1794099)).
- `HTMLDocument` is no longer serialized as a `WebElement` reference ([Firefox bug 1793920](https://bugzil.la/1793920)).
- `WebDriver:NewWindow` now opens a window with an `about:blank` tab instead of `about:newtab` ([Firefox bug 1533058](https://bugzil.la/1533058)).
## Changes for add-on developers
- Firefox now issues a warning when an extension is installed if its [version number](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/version) doesn't follow the recommended format ([Firefox bug 1793925](https://bugzil.la/1793925)).
## Older versions
{{Firefox_for_developers(107)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/73/index.md | ---
title: Firefox 73 for developers
slug: Mozilla/Firefox/Releases/73
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 73 that will affect developers. Firefox 73 was released on February 11, 2020.
## Changes for web developers
### Developer tools
- [CORS errors](/en-US/docs/Web/HTTP/CORS/Errors) now appear as errors in the console (and no longer as warnings) giving them the appropriate visibility ([Firefox bug 1602093](https://bugzil.la/1602093)).
- Text and regular expression searches in the web console [can now be negated by prefixing them with '-'](https://firefox-source-docs.mozilla.org/devtools-user/web_console/console_messages/index.html#filtering-and-searching) ([Firefox bug 1291192](https://bugzil.la/1291192)).
### HTML
_No changes._
### CSS
- We've implemented {{cssxref("overscroll-behavior-block")}} and {{cssxref("overscroll-behavior-inline")}}, the logical mappings for {{cssxref("overscroll-behavior-x")}} and {{cssxref("overscroll-behavior-y")}} ([Firefox bug 833953](https://bugzil.la/833953)).
#### Removals
- The proprietary `-moz-touch-enabled` media query has been removed ([Firefox bug 1486964](https://bugzil.la/1486964)). You should use [`pointer: coarse`](/en-US/docs/Web/CSS/@media/pointer) instead.
### SVG
- The {{SVGAttr("letter-spacing")}} and {{SVGAttr("word-spacing")}} properties now work in SVG ([Firefox bug 371787](https://bugzil.la/371787)).
### MathML
#### Removals
- The deprecated {{MathMLElement("mfenced")}} element has been removed ([Firefox bug 1603773](https://bugzil.la/1603773)). Use the {{MathMLElement("mrow")}} and {{MathMLElement("mo")}} elements instead.
### JavaScript
- The `yearName` and `relatedYear` fields have been made available in the [`DateTimeFormat.prototype.formatToParts()`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/formatToParts) method, enabling useful formatting options for CJK calendars ([Firefox bug 1591664](https://bugzil.la/1591664)).
### APIs
#### DOM
- The {{domxref("Window.innerWidth", "innerWidth")}} and {{domxref("Window.innerHeight", "innerHeight")}} properties on {{domxref("Window")}} objects have been updated to return the width and height of the layout viewport in all situations, rather than sometimes being based on the visual viewport. In particular, previously when using [Responsive Design Mode](https://firefox-source-docs.mozilla.org/devtools-user/responsive_design_mode/index.html), these returned the visual viewport dimensions, causing the behavior to vary from what was expected ([Firefox bug 1514429](https://bugzil.la/1514429)).
#### WebVR
- The deprecated [WebVR API](/en-US/docs/Web/API/WebVR_API)—which has been supplanted by [WebXR](/en-US/docs/Web/API/WebXR_Device_API), which supports both [augmented](https://en.wikipedia.org/wiki/Augmented_reality) and [virtual reality](https://en.wikipedia.org/wiki/Virtual_reality) applications—now [requires a secure context](/en-US/docs/Web/API/WebVR_API#api_availability) using the {{Glossary("HTTPS")}} protocol to operate. This is due to the availability of sensitive input sources that may include private information ([Firefox bug 1381645](https://bugzil.la/1381645)).
#### Removals
- Support for the {{domxref("VideoPlaybackQuality")}} property {{domxref("VideoPlaybackQuality.corruptedVideoFrames", "corruptedVideoFrames")}}, which has been deprecated in the specification, has been removed from Firefox ([Firefox bug 1602163](https://bugzil.la/1602163)).
### Security
_No changes._
### WebDriver conformance (Marionette)
- Added `WebDriver:Print` to print the current page as a PDF document ([Firefox bug 1604506](https://bugzil.la/1604506)).
- `Webdriver:TakeScreenshot` now always captures the top-level browsing context and not the currently-selected browsing context, if no element to capture has been specified ([Firefox bug 1398087](https://bugzil.la/1398087), [Firefox bug 1606794](https://bugzil.la/1606794)).
- Using `Webdriver:TakeScreenshot`'s `full` argument causes the complete page to be captured ([Firefox bug 1571424](https://bugzil.la/1571424)).
## Changes for add-on developers
### API changes
- The {{WebExtAPIRef("sidebarAction.toggle()")}} function has been implemented ([bug 1453355](https://bugzil.la/1453355)).
### Manifest changes
_No changes._
## See also
- Hacks blog post: [Firefox 73 is upon us](https://hacks.mozilla.org/2020/02/firefox-73-is-upon-us/)
## Older versions
{{Firefox_for_developers(72)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/54/index.md | ---
title: Firefox 54 for developers
slug: Mozilla/Firefox/Releases/54
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
Firefox 54 was released on June 13, 2017. This article lists key changes that are useful for web developers.
## Changes for Web developers
### Developer Tools
- The network request summary now includes the amount of data actually transferred ("transferred size"), as does the performance analysis view ([Firefox bug 1168376](https://bugzil.la/1168376)).
- The network request headers view now links to the related documentation on MDN ([Firefox bug 1320233](https://bugzil.la/1320233)).
### CSS
- {{cssxref("clip-path")}} now supports [basic shapes](/en-US/docs/Web/CSS/CSS_shapes) ([Firefox bug 1247229](https://bugzil.la/1247229)).
- Firefox's implementations of CSS Flexbox and CSS alignment now implement updated spec language for interactions between the properties {{cssxref("align-items")}} and {{cssxref("align-self")}} as well as between {{cssxref("justify-items")}} and {{cssxref("justify-self")}} ([Firefox bug 1340309](https://bugzil.la/1340309)).
- {{htmlelement("input")}} elements of types `checkbox` and `radio` with {{cssxref("appearance", "-moz-appearance")}}`: none;` set on them are now non-replaced elements, for compatibility with other browsers ([Firefox bug 605985](https://bugzil.la/605985)).
- Previously, an element styled with {{cssxref("display")}}: `inline-block` with a child element of type {{domxref("HTMLInputElement")}} styled with `display:block` had a wrong baseline ([Firefox bug 1330962](https://bugzil.la/1330962)). This is now fixed.
- When Mozilla introduced dedicated content threads to Firefox (through the Electrolysis or e10s project), support for styling {{HTMLElement("option")}} elements was removed temporarily. Starting in Firefox 54, you can apply foreground and background colors to `<option>` elements again, using the {{cssxref("color")}} and {{cssxref("background-color")}} attributes. See [Firefox bug 910022](https://bugzil.la/910022) for more information. Note that this is still disabled in Linux due to lack of contrast (see [Firefox bug 1338283](https://bugzil.la/1338283) for progress on this).
- [CSS Animations](/en-US/docs/Web/CSS/CSS_animations) now send the {{domxref("Element/animationcancel_event", "animationcancel")}} event as expected when an animation aborts prematurely ([Firefox bug 1302648](https://bugzil.la/1302648)).
- Transparent colors (i.e. those with an alpha channel of 0) were being serialized to the [`transparent` color keyword](/en-US/docs/Web/CSS/color_value) in certain situations; this has been fixed so that Firefox follows the spec (as well as other browsers' implementations). See ([Firefox bug 1339394](https://bugzil.la/1339394) for further information.
- The proprietary `:-moz-table-border-nonzero` pseudo-class is no longer available to web content; it is now restricted to Firefox's internal UA stylesheet ([Firefox bug 1341925](https://bugzil.la/1341925)).
- \[css-grid] Intrinsic content with overflow:auto overlaps in grid ([Firefox bug 1348857](https://bugzil.la/1348857)).
- \[css-grid] Transferred min-size contribution of percentage size grid item with an intrinsic ratio ([Firefox bug 1349320](https://bugzil.la/1349320)).
### JavaScript
- `\b` and `\B` in {{jsxref("RegExp")}} with the `"u"` (Unicode) and `"i"` (case insensitive) flags now treat U+017F (LATIN SMALL LETTER LONG S) and U+212A (KELVIN SIGN) as word characters ([Firefox bug 1338373](https://bugzil.la/1338373)).
- The {{jsxref("DataView")}} constructor now throws a {{jsxref("RangeError")}} if the `byteOffset` parameter is out of {{jsxref("Number.MAX_SAFE_INTEGER")}} (>= 2 \*\* 53) ([Firefox bug 1317382](https://bugzil.la/1317382)).
- The {{jsxref("Date.UTC()")}} method has been updated to conform to ECMAScript 2017 when fewer than two arguments are provided ([Firefox bug 1050755](https://bugzil.la/1050755)).
- The {{jsxref("Function.prototype.toString()")}} method has been updated to match the latest [proposed specification](https://tc39.es/Function-prototype-toString-revision/) ([Firefox bug 1317400](https://bugzil.la/1317400)).
### DOM & HTML DOM
- The {{domxref("URL.toJSON()")}} method has been implemented ([Firefox bug 1337702](https://bugzil.la/1337702)).
- The {{domxref("URLSearchParams.URLSearchParams", "URLSearchParams()")}} constructor now accepts a record containing strings as an init object ([Firefox bug 1331580](https://bugzil.la/1331580)).
- Values returned in {{domxref("KeyboardEvent.key")}} for printable keys when the control key is also pressed have been corrected on macOS (except when the Command key is pressed) ([Firefox bug 1342865](https://bugzil.la/1342865)).
- The `dom.workers.latestJSVersion` preference, which was mainly implemented to work around problems using [`let`](/en-US/docs/Web/JavaScript/Reference/Statements/let) in workers (due to [Firefox bug 855665](https://bugzil.la/855665), which has since been fixed) has been removed (see [Firefox bug 1219523](https://bugzil.la/1219523)).
- The {{domxref("event.timeStamp")}} property now returns a high-resolution monotonic time ({{domxref("DOMHighResTimeStamp")}}) instead of a value representing [Unix time](/en-US/docs/Glossary/Unix_time) in milliseconds.
### Web Workers and Service Workers
- `WorkerGlobalScope.close` is now available on {{domxref("DedicatedWorkerGlobalScope.close", "DedicatedWorkerGlobalScope")}} and {{domxref("SharedWorkerGlobalScope.close", "SharedWorkerGlobalScope")}} instead. This change was made to stop `close()` being available on service workers, as it isn't supposed to be used there and always throws an exception when called (see [Firefox bug 1336043](https://bugzil.la/1336043)).
- The {{domxref("origin")}} property has been implemented (see [Firefox bug 1306170](https://bugzil.la/1306170)).
- The {{domxref("Client.type")}} property has been implemented (see [Firefox bug 1339844](https://bugzil.la/1339844)).
- {{domxref("Clients.matchAll()")}} now returns {{domxref("Client")}} objects in most recently focused order (see [Firefox bug 1266747](https://bugzil.la/1266747)).
- Some changes have been made to the observed behavior when the {{domxref("Request.Request","Request()")}} constructor is passed an existing {{domxref("Request")}} object instance to make a new instance. The following new behaviors are designed to retain security while making the constructor less likely to throw exceptions:
- If this object exists on another origin to the constructor call, the {{domxref("Request.referrer")}} is stripped out.
- If this object has a {{domxref("Request.mode")}} of `navigate`, the `mode` value is converted to `same-origin`.
### Audio/Video
#### General
- 5.1 surround sound playback is now enabled by default on Windows, macOS, and Linux ([Firefox bug 1334508](https://bugzil.la/1334508), [Firefox bug 1321502](https://bugzil.la/1321502), and [Firefox bug 1323659](https://bugzil.la/1323659)).
#### Media Capture and Streams API
- Usage of a {{domxref("MediaStream")}} object as the input parameter to {{domxref("URL.createObjectURL_static", "URL.createObjectURL()")}} has been deprecated — the console will now show a warning (see [Firefox bug 1334564](https://bugzil.la/1334564)). You are advised to use {{domxref("HTMLMediaElement.srcObject")}} instead.
#### Web Audio API
- The method {{domxref("AnalyserNode.getFloatFrequencyData()")}} now correctly represents silent samples in the returned buffer with the value `-Infinity` ([Firefox bug 1336098](https://bugzil.la/1336098)).
- {{domxref("AudioParam.setValueCurveAtTime()")}} now throws a `TypeError` exception if any of the specified values aren't finite ([Firefox bug 1308437](https://bugzil.la/1308437)).
#### Encrypted MediaExtensions API
- The `MediaKeySession.keySystem` string has been removed from the specification, and as such we've taken it out of Firefox 54 ([Firefox bug 1335555](https://bugzil.la/1335555)).
- Support has been added for the VP9 codec in encrypted streams using [Clear Key](https://www.w3.org/TR/encrypted-media/#clear-key) and [Widevine](https://www.widevine.com/) ([Firefox bug 1338064](https://bugzil.la/1338064)).
- Previously, MSE was only allowed to use WebM/VP8 video if the system was considered "fast enough." Now playback of VP8-encoded `webm/video` media is always supported, regardless of system performance.
#### WebRTC
- TCP ICE candidate support, originally added in Firefox 41, is now enabled by default. This allows the ICE layer to consider candidates that use TCP rather than the preferred UDP for transmission. This can be useful in environments in which UDP is blocked ([Firefox bug 1176382](https://bugzil.la/1176382)). This [blog post](https://blog.mozilla.org/webrtc/active-ice-tcp-punch-firewalls-directly/) explains the feature in more details.
## Removals from the web platform
### CSS
- Removed the `-moz` prefixed versions of `isolate`, `isolate-override`, and `plaintext` values for the {{cssxref("unicode-bidi")}} property ([Firefox bug 1333675](https://bugzil.la/1333675)).
### HTTP
- HTTP/1 Pipelining support has been removed in Firefox 54. Maintaining it as we make the move into a new world full of HTTP/2 and other substantial, standardized improvements to networking performance is not worthwhile given pipelining's compatibility and performance issues. The `network.http.pipelining` preference (as well as the other preferences that start with "network.http.pipelining") is now ignored. See [Firefox bug 1340655](https://bugzil.la/1340655) for further information.
## Older versions
{{Firefox_for_developers(53)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/79/index.md | ---
title: Firefox 79 for developers
slug: Mozilla/Firefox/Releases/79
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 79 that will affect developers. Firefox 79 was released on July 28, 2020.
See also [Firefox 79: The safe return of shared memory, new tooling, and platform updates](https://hacks.mozilla.org/2020/07/firefox-79/) on Mozilla hacks.
## Changes for web developers
### Developer Tools
#### Console
- Network messages with response codes in the 400-499 and 500-599 ranges are now considered errors, and are displayed [even if Response or XHR filters are disabled](https://firefox-source-docs.mozilla.org/devtools-user/web_console/console_messages/index.html#filtering-by-category). ([Firefox bug 1635460](https://bugzil.la/1635460))
- Network messages for requests that are blocked (by the browser or an extension) are now styled with a "prohibited" icon in the [Console](https://firefox-source-docs.mozilla.org/devtools-user/web_console/console_messages/index.html). ([Firefox bug 1629875](https://bugzil.la/1629875))
#### Debugger
- ["Blackbox" a source file](https://firefox-source-docs.mozilla.org/devtools-user/debugger/how_to/ignoring_sources/index.html) is now called "ignore" a source file. ([Firefox bug 1642811](https://bugzil.la/1642811))
- Inline preview is now available on [exceptions](https://firefox-source-docs.mozilla.org/devtools-user/debugger/how_to/breaking_on_exceptions/index.html). ([Firefox bug 1581708](https://bugzil.la/1581708))
- Items in the Watch Expressions and Scopes sections now have tooltips on hover, showing their values ([Firefox bug 1631545](https://bugzil.la/1631545))
- In the [Call Stack section](https://firefox-source-docs.mozilla.org/devtools-user/debugger/ui_tour/index.html#call-stack), there is now a context menu option to **Restart Frame**, to execute the current stack frame from its beginning. ([Firefox bug 1594467](https://bugzil.la/1594467))
#### Other tools
- The new [Application panel](https://firefox-source-docs.mozilla.org/devtools-user/application/index.html) is now available, which initially provides inspection and debugging support for [service workers](/en-US/docs/Web/API/Service_Worker_API) and [web app manifests](/en-US/docs/Web/Manifest).
- The Messages tab of the Network Monitor has been merged with the [Responses tab](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_details/index.html#response-tab). ([Firefox bug 1636421](https://bugzil.la/1636421))
- The Accessibility Inspector is automatically turned on when you access its tab; you no longer need to explicitly enable it. ([Firefox bug 1602075](https://bugzil.la/1602075))
- In [Responsive Design Mode](https://firefox-source-docs.mozilla.org/devtools-user/responsive_design_mode/index.html#controlling-responsive-design-mode), when touch simulation is enabled, mouse-drag events are now interpreted as touch-drag or swipe events. ([Firefox bug 1621781](https://bugzil.la/1621781))
- When [remote debugging](https://firefox-source-docs.mozilla.org/devtools-user/about_colon_debugging/index.html#connecting-to-a-remote-device), the URL bar now has **Back** and **Forward** buttons to help with navigation on the remote browser. ([Firefox bug 1639425](https://bugzil.la/1639425))
### HTML
- The [`<iframe>`](/en-US/docs/Web/HTML/Element/iframe) element's `sandbox` attribute now supports the `allow-top-navigation-by-user-activation` token ([Firefox bug 1359867](https://bugzil.la/1359867)).
- Setting `target="_blank"` on [`<a>`](/en-US/docs/Web/HTML/Element/a) and [`<area>`](/en-US/docs/Web/HTML/Element/area) elements implicitly provides the same behavior as also setting `rel="noopener"` ([Firefox bug 1522083](https://bugzil.la/1522083)).
### CSS
- External style sheets are now cached per document group ([Firefox bug 1599160](https://bugzil.la/1599160)). Firefox will minimize retrieval and revalidation of cached style sheets when navigating pages on the same origin. A simple reload (for example, `F5`) will not revalidate the cached CSS files. To load current versions of the style sheets, reload the page bypassing the cache (`Cmd`/`Ctrl` + `F5`).
#### Removals
- The [`prefers-color-scheme`](/en-US/docs/Web/CSS/@media/prefers-color-scheme) media feature's `no-preference` value has been removed from the [media queries spec](https://drafts.csswg.org/mediaqueries-5/#descdef-media-prefers-color-scheme), and from Firefox ([Firefox bug 1643656](https://bugzil.la/1643656)).
### JavaScript
- {{jsxref("SharedArrayBuffer")}} has been re-enabled in a post-Spectre-safe manner. It is available to cross-origin isolated sites ([Firefox bug 1619649](https://bugzil.la/1619649)).
- To cross-origin isolate your site, you need to set the new {{HTTPHeader("Cross-Origin-Embedder-Policy")}} (COEP) and {{HTTPHeader("Cross-Origin-Opener-Policy")}} (COOP) headers.
- {{jsxref("Promise.any()")}} is now available ([Firefox bug 1599769](https://bugzil.la/1599769)).
- {{jsxref("WeakRef")}} objects have been implemented ([Firefox bug 1639246](https://bugzil.la/1639246)).
- [Logical assignment operators](https://github.com/tc39/proposal-logical-assignment) are now supported ([Firefox bug 1639591](https://bugzil.la/1639591))
- [Logical nullish assignment (`??=`)](/en-US/docs/Web/JavaScript/Reference/Operators/Nullish_coalescing_assignment)
- [Logical AND assignment (`&&=`)](/en-US/docs/Web/JavaScript/Reference/Operators/Logical_AND_assignment)
- [Logical OR assignment (`||=`)](/en-US/docs/Web/JavaScript/Reference/Operators/Logical_OR_assignment)
- {{jsxref("Atomics")}} objects now also work with non-shared memory ([Firefox bug 1630706](https://bugzil.la/1630706)).
- The [`Intl.DateTimeFormat()` constructor](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/DateTimeFormat) now supports the `dateStyle` and `timeStyle` options ([Firefox bug 1557718](https://bugzil.la/1557718)).
- The [`Intl.NumberFormat()` constructor](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat) now supports more numbering systems ([Firefox bug 1413504](https://bugzil.la/1413504)).
### HTTP
- Cross-origin isolation has been implemented using the new {{HTTPHeader("Cross-Origin-Embedder-Policy")}} (COEP) and {{HTTPHeader("Cross-Origin-Opener-Policy")}} (COOP) headers. This allows you to access certain features such as {{jsxref("SharedArrayBuffer")}} objects and unthrottled timers in {{domxref("Performance.now()")}}.
### APIs
#### DOM
- The [`FileReader`](/en-US/docs/Web/API/FileReader) interface's [`loadstart` event](/en-US/docs/Web/API/FileReader/loadstart_event) is now dispatched asynchronously, as per the spec ([Firefox bug 1502403](https://bugzil.la/1502403)).
- {{domxref("CanvasPattern.setTransform()")}} now supports a {{domxref("DOMMatrix")}} object as an input parameter, as well as an `SVGMatrix` object ([Firefox bug 1565997](https://bugzil.la/1565997)).
#### Media, WebRTC, and Web Audio
- Firefox now supports remote timestamps on statistics records whose {{domxref("RTCStatsReport", "RTCStats.type")}} is `remote-outbound-rtp`. The {{domxref("RTCRemoteOutboundRtpStreamStats")}} dictionary which is used to provide these statistics now includes the {{domxref("RTCRemoteOutboundRtpStreamStats.remoteTimestamp", "remoteTimestamp")}} property, which states the timestamp on the remote peer at which the statistics were collected or generated ([Firefox bug 1615191](https://bugzil.la/1615191)).
#### Removals
- A number of internal Gecko events — including `DOMWindowClose` — which were accidentally exposed to the web, are now internal-only as intended ([Firefox bug 1557407](https://bugzil.la/1557407)).
### WebAssembly
- [WebAssembly Bulk memory operations](/en-US/docs/WebAssembly/Understanding_the_text_format#bulk_memory_operations) are now shipped ([Firefox bug 1528294](https://bugzil.la/1528294)).
- [WebAssembly Reference types](/en-US/docs/WebAssembly/Understanding_the_text_format#reference_types) are now shipped ([Firefox bug 1637884](https://bugzil.la/1637884)).
- [WebAssembly Threads](/en-US/docs/WebAssembly/Understanding_the_text_format#webassembly_threads) (Shared memory & Atomics) are now shipped ([Firefox bug 1389458](https://bugzil.la/1389458), [Firefox bug 1648685](https://bugzil.la/1648685)).
## Changes for add-on developers
- New API: [`tabs.warmup()`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/tabs/warmup) ([bug 1402256](https://bugzil.la/1402256))
- [Storage quotas are now enforced for the `sync` storage area](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/storage/sync#storage_quotas_for_sync_data) ([bug 1634615](https://bugzil.la/1634615)) ([addons.mozilla.org blog post](https://blog.mozilla.org/addons/2020/07/09/changes-to-storage-sync-in-firefox-79/))
## Older versions
{{Firefox_for_developers(78)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/117/index.md | ---
title: Firefox 117 for developers
slug: Mozilla/Firefox/Releases/117
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 117 that affect developers. Firefox 117 was released on August 29, 2023.
## Changes for web developers
### HTML
No notable changes.
### CSS
- The [CSS Nesting](/en-US/docs/Web/CSS/CSS_nesting) module is now supported in Firefox, along with the [`&` nesting selector](/en-US/docs/Web/CSS/Nesting_selector). This allows developers to write nested CSS, which helps with the readability, modularity, and maintainability of CSS stylesheets. It also potentially helps reduce CSS file size, decreasing download sizes. ([Firefox bug 1835066](https://bugzil.la/1835066), [Firefox bug 1840781](https://bugzil.la/1840781))
- The [`math-style`](/en-US/docs/Web/CSS/math-style) and [`math-depth`](/en-US/docs/Web/CSS/math-depth) properties are now supported, as well as the `math` value for the [`font-size`](/en-US/docs/Web/CSS/font-size#values) property ([Firefox bug 1845516](https://bugzil.la/1845516)).
- The [`contain-intrinsic-size: auto none`](/en-US/docs/Web/CSS/contain-intrinsic-size) syntax is now supported, which allows for using the last-remembered size of an element if possible and falls back to `contain-intrinsic-size: none` otherwise.
This is useful for grid and multi-column layouts to allow elements to be laid out as though they have no contents instead of 0px height ([Firefox bug 1835813](https://bugzil.la/1835813)).
### JavaScript
No notable changes.
### SVG
- Inline SVGs now support `<script>` elements with `type="module"`, `defer`, and `async` attributes.
This allows SVGs to use modern JavaScript features, including ES modules, and to load scripts asynchronously ([Firefox bug 1839954](https://bugzil.la/1839954)).
### HTTP
- Fixed a bug where the [Content-Security-Policy](/en-US/docs/Web/HTTP/CSP) `'strict-dynamic'` source expression was not being enforced in `default-src` directives.
The behavior now matches the specification where `default-src` directive values are used as a fallback when `script-src` is not provided ([Firefox bug 1313937](https://bugzil.la/1313937)).
- The `Range` header is now a [CORS-safelisted request header](/en-US/docs/Glossary/CORS-safelisted_request_header) when the value is a single byte range (e.g., `bytes=100-200`).
This allows the `Range` header to be used in cross-origin requests without triggering a preflight request, which is useful for requesting media and resuming downloads ([Firefox bug 1733981](https://bugzil.la/1733981)).
### APIs
- The {{domxref("CanvasRenderingContext2D.getContextAttributes()")}} method can now be used to get the 2D context attributes being used by the browser ([Firefox bug 1517786](https://bugzil.la/1517786)).
- The {{domxref("ReadableStream/from_static", "ReadableStream.from()")}} static member is now supported, allowing developers to construct a readable stream from any iterable or async iterable object ([Firefox bug 1772772](https://bugzil.la/1772772)).
- [WebRTC Encoded Transforms](/en-US/docs/Web/API/WebRTC_API/Using_Encoded_Transforms) are now supported, allowing web applications to modify incoming and outgoing WebRTC encoded video and audio frames using a {{DOMxRef("TransformStream")}} running in a worker.
The supported interfaces include: {{domxref("RTCRtpScriptTransform")}}, {{domxref("RTCRtpScriptTransformer")}}, {{domxref("RTCRtpSender.transform")}}, {{domxref("RTCRtpReceiver.transform")}}, {{domxref("RTCEncodedVideoFrame")}}, and {{domxref("RTCEncodedAudioFrame")}}, and the {{domxref("RTCTransformEvent")}} and worker {{domxref("DedicatedWorkerGlobalScope.rtctransform_event", "rtctransform")}} event ([Firefox bug 1631263](https://bugzil.la/1631263)).
- [`CSSStyleRule`](/en-US/docs/Web/API/CSSStyleRule) now inherits from [`CSSGroupingRule`](/en-US/docs/Web/API/CSSGroupingRule) instead of directly from [`CSSRule`](/en-US/docs/Web/API/CSSRule). As a result, it additionally implements the property [`cssRules`](/en-US/docs/Web/API/CSSGroupingRule/cssRules) and the methods [`deleteRule()`](/en-US/docs/Web/API/CSSGroupingRule/cssRules) and [`insertRule()`](/en-US/docs/Web/API/CSSGroupingRule/insertRule) (Firefox bug [1846251](https://bugzil.la/1846251)).
### WebDriver conformance (WebDriver BiDi, Marionette)
#### WebDriver BiDi
- Added the `browser.close` command that allows users to terminate all WebDriver sessions and close the browser ([Firefox bug 1829334](https://bugzil.la/1829334)).
- Added the `browsingContext.setViewport` command that allows users to change the dimensions of a top level browsing context ([Firefox bug 1838664](https://bugzil.la/1838664)).
- Added the `browsingContext.fragmentNavigated` event which is emitted for same-document navigations ([Firefox bug 1841039](https://bugzil.la/1841039)).
- Added support for the `background` argument of the `browsingContext.create` command, which will force the new context to be created in the background. This argument is optional and defaults to `false`, meaning that `browsingContext.create` now opens new contexts in the foreground by default ([Firefox bug 1843507](https://bugzil.la/1843507)).
- Added support for the `clip` argument of the `browsingContext.captureScreenshot` command, which allows to restrict the screenshot either to a specific area or to an element. When clipping to an element, you can optionally scroll the element into view before taking the screenshot ([Firefox bug 1840998](https://bugzil.la/1840998)).
- All commands and events related to a navigation will now provide a `navigation` id, which is a `UUID` identifying a specific navigation. This property is available in the `browsingContext.navigate` response, in the `browsingContext.load`, `browsingContext.domContentLoaded`, `browsingContext.fragmentNavigated` events, as well as in all `network` events created for a navigation request ([Firefox bug 1763122](https://bugzil.la/1763122), [Firefox bug 1789484](https://bugzil.la/1789484), [Firefox bug 1805405](https://bugzil.la/1805405)).
- `headers` and `cookies` in `network` events are now serialized as `network.BytesValue`, which will provide a better support for non-UTF8 values ([Firefox bug 1842619](https://bugzil.la/1842619)).
- The `browsingContext.create` command will now wait until the created context has a valid size ([Firefox bug 1847044](https://bugzil.la/1847044)).
### Developer tools
- The Network Monitor now shows information about proxied requests, including the proxy address, the proxy status, and the proxy HTTP version in the [Headers tab](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_details/index.html) ([Firefox bug 1707192](https://bugzil.la/1707192)).
- The area selected by the [Measuring Tool](https://firefox-source-docs.mozilla.org/devtools-user/measure_a_portion_of_the_page/index.html) can now be resized and moved using keyboard shortcuts.
Pressing the arrow keys moves the selected area, while pressing <kbd>Ctrl</kbd> + arrow keys (or <kbd>Cmd</kbd> + arrow keys on a Mac) resizes the selected area.
Holding down the <kbd>Shift</kbd> key accelerates the moving and resizing actions when using these key combinations ([Firefox bug 1262782](https://bugzil.la/1262782)).
- Properties that are not supported in highlight pseudo-elements ([`::highlight()`](/en-US/docs/Web/CSS/::highlight), [`::target-text`](/en-US/docs/Web/CSS/::target-text), [`::spelling-error`](/en-US/docs/Web/CSS/::spelling-error), [`::grammar-error`](/en-US/docs/Web/CSS/::grammar-error), and [`::selection`](/en-US/docs/Web/CSS/::selection)) are now reported in the [Page Inspector](https://firefox-source-docs.mozilla.org/devtools-user/#page-inspector) CSS rules panel ([Firefox bug 1842157](https://bugzil.la/1842157)).
## Changes for add-on developers
No notable changes.
## Older versions
{{Firefox_for_developers(116)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/43/index.md | ---
title: Firefox 43 for developers
slug: Mozilla/Firefox/Releases/43
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
[To test the latest developer features of Firefox, install Firefox Developer Edition](https://www.mozilla.org/firefox/developer/) Firefox 43 was released on December 15, 2015. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.
## Changes for Web developers
### Developer Tools
Highlights:
- [Server logging in the Web Console](https://firefox-source-docs.mozilla.org/devtools-user/web_console/console_messages/index.html#server)
- [Quickly find the rule that overrode a CSS declaration](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_css/index.html#overridden-declarations)
- ["Use in Console" context menu item in Inspector](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_html/index.html#element-popup-menu)
- ["Strict" option for filtering in the Rules view](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_css/index.html#strict-search)
- [Network entries in the Console now link to the Network Monitor](https://firefox-source-docs.mozilla.org/devtools-user/web_console/console_messages/index.html#network)
- [Markup view shows indicators for pseudo-classes locked for elements](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_css/index.html#setting-hover-active-focus)
- New sidebar UI for WebIDE
[All devtools bugs fixed between Firefox 42 and Firefox 43](https://bugzilla.mozilla.org/buglist.cgi?resolution=FIXED&classification=Client%20Software&chfieldto=2015-09-19&query_format=advanced&chfield=resolution&chfieldfrom=2015-08-10&chfieldvalue=FIXED&bug_status=RESOLVED&bug_status=VERIFIED&component=Developer%20Tools&component=Developer%20Tools%3A%203D%20View&component=Developer%20Tools%3A%20Canvas%20Debugger&component=Developer%20Tools%3A%20Console&component=Developer%20Tools%3A%20Debugger&component=Developer%20Tools%3A%20Framework&component=Developer%20Tools%3A%20Graphic%20Commandline%20and%20Toolbar&component=Developer%20Tools%3A%20Inspector&component=Developer%20Tools%3A%20Memory&component=Developer%20Tools%3A%20Netmonitor&component=Developer%20Tools%3A%20Object%20Inspector&component=Developer%20Tools%3A%20Performance%20Tools%20%28Profiler%2FTimeline%29&component=Developer%20Tools%3A%20Responsive%20Mode&component=Developer%20Tools%3A%20Scratchpad&component=Developer%20Tools%3A%20Source%20Editor&component=Developer%20Tools%3A%20Storage%20Inspector&component=Developer%20Tools%3A%20Style%20Editor&component=Developer%20Tools%3A%20User%20Stories&component=Developer%20Tools%3A%20Web%20Audio%20Editor&component=Developer%20Tools%3A%20WebGL%20Shader%20Editor&component=Developer%20Tools%3A%20WebIDE&product=Firefox&list_id=12582678).
### CSS
- Support for the standard, unprefixed version of {{Cssxref("hyphens")}} has been landed ([Firefox bug 953408](https://bugzil.la/953408)).
- The shorthand property {{cssxref("font")}} has been updated to accept {{cssxref("font-stretch")}} values ([Firefox bug 1057680](https://bugzil.la/1057680)).
- To match the latest evolution of the specification, the {{cssxref(":fullscreen")}} pseudo-class now selects the whole stack of elements in full screen, and not only the top-level one ([Firefox bug 1199522](https://bugzil.la/1199522)).
- The deprecated SVG values for the {{cssxref("writing-mode")}}, `lr`, `lr-tb`, `rl`, `tb`, and `tb-rl`, have been added in CSS as aliases to standard properties ([Firefox bug 1205787](https://bugzil.la/1205787)).
### HTML
- For {{htmlelement("img")}} with ICO image containing multiple frames, the intrinsic dimension of the image is set to the one of the largest frame, and no more of the smallest frame [Firefox bug 1201796](https://bugzil.la/1201796).
- The value of the document's viewport (defined with `<meta name="viewport>`)can now dynamically be changed via JavaScript ([Firefox bug 976616](https://bugzil.la/976616)).
### JavaScript
#### New APIs
- The new ES2016 methods {{jsxref("Array.prototype.includes()")}} and {{jsxref("TypedArray.prototype.includes()")}} are now enabled by default ([Firefox bug 1070767](https://bugzil.la/1070767)).
#### Changes regarding the `arguments` object
- To match the ES2015 specification, [arrow functions](/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions) no longer have their own [`arguments`](/en-US/docs/Web/JavaScript/Reference/Functions/arguments) object. The `arguments` object is now lexically bound (inherited from the outer function). In most cases, [rest parameters](/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters) are a good alternative `(...args) => args[i]`, see [Firefox bug 889158](https://bugzil.la/889158).
- The [arguments](/en-US/docs/Web/JavaScript/Reference/Functions/arguments) object is now allowed in conjunction with [rest parameters](/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters) ([Firefox bug 1133298](https://bugzil.la/1133298)).
- From now on, a mapped [`arguments`](/en-US/docs/Web/JavaScript/Reference/Functions/arguments) object in non-strict functions is only provided if the function does **not** contain any [rest parameters](/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters), any [default parameters](/en-US/docs/Web/JavaScript/Reference/Functions/Default_parameters) or any [destructured parameters](/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment) ([Firefox bug 1175394](https://bugzil.la/1175394)).
#### Other changes
- [Generators](/en-US/docs/Web/JavaScript/Reference/Statements/function*) and [generator methods](/en-US/docs/Web/JavaScript/Reference/Functions/Method_definitions) are no longer constructable as per ES2016 ([Firefox bug 1191486](https://bugzil.la/1191486)).
### Interfaces/APIs/DOM
#### DOM & HTML DOM
_No change._
#### IndexedDB
- A new feature called [locale-aware sorting](/en-US/docs/Web/API/IndexedDB_API/Using_IndexedDB#locale-aware_sorting) has been added allowing for the creation of indexes with a locale specified, which can then be used to sort data according to the rules of that locale ([Firefox bug 871846](https://bugzil.la/871846)). This is a non-standard Firefox-specific feature.
#### Service Workers
- As per the specification, if {{domxref("ExtendableEvent.waitUntil()")}} is called outside of the {{domxref("ExtendableEvent")}} handler, Firefox will now throw an `InvalidStateError`; in addition, multiple calls to {{domxref("ExtendableEvent.waitUntil","waitUntil()")}} will now stack up, and the resulting promises will be added to the list of [extend lifetime promises](https://slightlyoff.github.io/ServiceWorker/spec/service_worker/index.html#dfn-extend-lifetime-promises) ([Firefox bug 1180274](https://bugzil.la/1180274)).
- {{domxref("PushMessageData")}} methods have been implemented ([Firefox bug 1149195](https://bugzil.la/1149195)).
#### WebRTC
- The {{domxref("HTMLCanvasElement.captureStream()")}} method has been activated by default ([Firefox bug 1177276](https://bugzil.la/1177276)).
- The non-standard constraint style option list for `RTCOfferOptions` has been deprecated and will be removed entirely in Firefox 44.
#### Miscellaneous
- The [Battery Status API](/en-US/docs/Web/API/Battery_Status_API) now uses the new promise syntax for {{domxref("Navigator.getBattery()")}}, as specified in the recent evolution of the specification ([Firefox bug 1050749](https://bugzil.la/1050749)).
- The `User-Agent` header is no longer in the list of {{Glossary("Forbidden_header_name", "forbidden header names")}} so it can now be set in a [Fetch](/en-US/docs/Web/API/Fetch_API) {{domxref("Headers")}} object, via XHR {{domxref("XMLHttpRequest.setRequestHeader()")}},… ([Firefox bug 1188932](https://bugzil.la/1188932)).
- The {{domxref("MediaRecorder.MediaRecorder", "MediaRecorder()")}} constructor can now accept an options dictionary as a parameter, which allows you to set custom bitrates for the audio/video to be recorded ([Firefox bug 1161276](https://bugzil.la/1161276)).
- The {{domxref("PerformanceObserver")}} interface, belonging to the [Performance APIs](/en-US/docs/Web/API/Performance_API) has been implemented ([Firefox bug 1165796](https://bugzil.la/1165796)).
- The Frame Timing API has been added: the `PerformanceRenderTiming` and `PerformanceCompositeTiming` interfaces are now available ([Firefox bug 1191178](https://bugzil.la/1191178)).
- The modern [Screen Orientation API](/en-US/docs/Web/API/Screen_Orientation_API) has been implemented: unprefixed {{domxref("Screen.orientation")}} and the {{domxref("ScreenOrientation")}} interface are now available ([Firefox bug 1131470](https://bugzil.la/1131470)). The non-standard `Screen.mozOrientation`, `Screen.onmozorientationchange`, `Screen.mozLockOrientation()`, and `Screen.mozUnlockOrientation()` will be removed in the future.
- Under Linux, like under Windows, {{domxref("Event.timeStamp")}} now returns a {{domxref("DOMHighResTimeStamp")}} ([Firefox bug 1026803](https://bugzil.la/1026803)).
- Experimental support for {{domxref("Selection")}} events {{domxref("Document/selectionchange_event", "selectionchange")}} and {{domxref("Node/selectstart_event", "selectstart")}}, as well as the {{domxref("Document.selectionchange_event", "Document.onselectionchange")}} and {{domxref("Node/selectstart_event", "HTMLInputElement.onselectstart")}} event handlers property has been added ([Firefox bug 571294](https://bugzil.la/571294)). The `selectionchange` event is fired on the {{domxref("Document")}} if the associated `Selection` object is concerned, or on the specific {{domxref("HTMLInputElement")}} or {{domxref("HTMLTextAreaElement")}} ([Firefox bug 1196479](https://bugzil.la/1196479)). This feature is controlled by the `dom.select_events.enabled` preference, which defaults to `false`, except on Nightly.
- Support for {{domxref("MouseEvent.offsetX")}} and {{domxref("MouseEvent.offsetY")}} have been activated on Firefox for Android and Firefox OS ([Firefox bug 1204841](https://bugzil.la/1204841)).
- The `HTMLCanvasElement.mozFetchAsStream()` method has been removed ([Firefox bug 1206030](https://bugzil.la/1206030)).
- The constructor {{domxref("Request.Request", "Request()")}} as well as {{domxref("fetch()")}} will now raise a {{jsxref("TypeError")}} exception when used with a URL containing a username and password ([Firefox bug 1195820](https://bugzil.la/1195820)).
### MathML
_No change._
### SVG
_No change._
### Audio/Video
_No change._
## HTTP
_No change._
## Networking
_No change._
## Security
- Access to Web Storage (i.e. `localStorage` and `sessionStorage`) from third-party IFrames is now denied if the user has [disabled third-party cookies](https://support.mozilla.org/en-US/kb/third-party-cookies-firefox-tracking-protection) ([Firefox bug 536509](https://bugzil.la/536509)).
- This whitelist has even been removed in Nightly and Aurora/Dev Edition of the browser ([Firefox bug 1201023](https://bugzil.la/1201023)). It is currently scheduled that this removal will also happen for Beta and Release versions for the next version (Firefox 44).
- Subresource integrity has been implemented for {{htmlelement("script")}} and {{htmlelement("link")}} that links to stylesheets ([Firefox bug 992096](https://bugzil.la/992096)).
## Changes for add-on and Mozilla developers
### Interfaces
_No change._
### XUL
_No change._
### JavaScript code modules
_No change._
### XPCOM
_No change._
### Plugins
- In preparation for future releases to switch over to multi-process content, [NPAPI](/en-US/docs/Glossary/Plugin) plugins can no longer be run in the same process as the page content. The preferences starting with `dom.ipc.plugins` are no longer used.
### Other
_No change._
## Older versions
{{Firefox_for_developers('42')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/27/index.md | ---
title: Firefox 27 for developers
slug: Mozilla/Firefox/Releases/27
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
Firefox 27 was released on February 4, 2014. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.
## Changes for Web developers
### Developer Tools
- Breakpoints can now be set on DOM events.
- JavaScript in the debugger panel can be unminified, using the { } button.
- The inspector now has an "edit-element-html" feature, without needing an add-on.
- Background-URLs and colors have preview in inspector. Even hovering over canvas elements will give a pop-up with an image preview.
- Reflow logging has been added.
- Styles of SVG elements are now inspectable ([Firefox bug 921191](https://bugzil.la/921191)).
- Failure to find the image when clicking URL link in CSS inspector has been fixed ([Firefox bug 921686](https://bugzil.la/921686)).
- The {{HTTPHeader("SourceMap", "X-SourceMap")}} header is now supported ([Firefox bug 765993](https://bugzil.la/765993)).
More details in [this post](https://hacks.mozilla.org/2013/11/firefox-developer-tools-episode-27-edit-as-html-codemirror-more/).
### CSS
- The `-moz-grab` and `-moz-grabbing` keywords on the CSS {{cssxref("cursor")}} property have been unprefixed to `grab` and `grabbing` ([Firefox bug 880672](https://bugzil.la/880672)).
- Support for the `-moz-hsla()` and `-moz-rgba()` functional notations has been dropped. Only the unprefixed versions, `hsla()` and `rgba()` are supported from now on ([Firefox bug 893319](https://bugzil.la/893319)).
- The "`true`" value for {{cssxref("text-align")}} has been added ([Firefox bug 929991](https://bugzil.la/929991)).
- Experimental support of `position:sticky` is now active by default on non-release builds ([Firefox bug 902992](https://bugzil.la/902992)). For releases builds, the `layout.css.sticky.enabled` preference still needs to be set to `true`.
- The {{cssxref("all")}} shorthand property has been added ([Firefox bug 842329](https://bugzil.la/842329)).
- The {{cssxref("unset")}} global value has been added; it allows to reset any CSS property ([Firefox bug 921731](https://bugzil.la/921731)).
- Curly braces are no longer allowed in HTML `style` attributes: doing `<div style="{ display: none }">` was working in quirks mode, but won't anymore [Firefox bug 915053](https://bugzil.la/915053).
- The {{cssxref("overflow")}} property now works on {{HTMLElement("fieldset")}} ([Firefox bug 261037](https://bugzil.la/261037)).
### HTML
- The `color` value of the {{HTMLElement("input")}} [`type`](/en-US/docs/Web/HTML/Element/input#type) attribute has been implemented on desktop platforms. It was already available on mobile ones.
- The `allow-popups` directive is now supported with the [`sandbox`](/en-US/docs/Web/HTML/Element/iframe#sandbox) attribute of the {{HTMLElement("iframe")}} element ([Firefox bug 766282](https://bugzil.la/766282)).
- Blending of HTML elements using the {{cssxref("mix-blend-mode")}} property has been implemented. The `layout.css.mix-blend-mode.enabled` preference must be set to `true` ([Firefox bug 902525](https://bugzil.la/902525)).
- The {{domxref("Object.typeMustMatch", "typeMustMatch")}} property of the {{HTMLElement("object")}} element is now supported ([Firefox bug 827160](https://bugzil.la/827160)).
### JavaScript
[ECMAScript 2015](/en-US/docs/Web/JavaScript/ECMAScript_6_support_in_Mozilla) implementation continues!
- The [spread operator](/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax) is now supported in Function calls ([Firefox bug 762363](https://bugzil.la/762363)).
- The mathematical function {{jsxref("Global_Objects/Math/hypot", "Math.hypot()")}} has been implemented ([Firefox bug 896264](https://bugzil.la/896264)).
- The {{jsxref("Operators/yield*", "yield*")}} expression is now implemented ([Firefox bug 666396](https://bugzil.la/666396)).
- The `MapIterator`, `SetIterator` and `ArrayIterator` objects now match the specification ([Firefox bug 881226](https://bugzil.la/881226)).
- [for...of](/en-US/docs/Web/JavaScript/Reference/Statements/for...of) loops now expect the ES2015 standard [iterator protocol](/en-US/docs/Web/JavaScript/Reference/Iteration_protocols) moving away from SpiderMonkey old iterator protocol using `StopIteration`.
- {{jsxref("String.match")}} and {{jsxref("String.replace")}} now reset {{jsxref("RegExp.lastIndex")}} ([Firefox bug 501739](https://bugzil.la/501739)).
### Interfaces/APIs/DOM
- Support for the two `setRange()` methods on the {{domxref("HTMLInputElement")}} interface has been added ([Firefox bug 850364](https://bugzil.la/850364)).
- Support for the two `setRange()` methods on the {{domxref("HTMLTextAreaElement")}} interface has been added ([Firefox bug 918940](https://bugzil.la/918940)).
- The methods `getAllKeys()` and `openKeyCursor()` have been added to {{domxref("IDBObjectStore")}} ([Firefox bug 920633](https://bugzil.la/920633) and [Firefox bug 920800](https://bugzil.la/920800)).
- The {{domxref("HTMLFormControlsCollection")}} interface has been implemented ([Firefox bug 913920](https://bugzil.la/913920)).
- The {{domxref("CanvasRenderingContext2D")}} interface now supports the two methods {{domxref("CanvasRenderingContext2D.getLineDash()", "getLineDash()")}} and {{domxref("CanvasRenderingContext2D.setLineDash()", "setLineDash()")}} and the {{domxref("CanvasRenderingContext2D.lineDashOffset", "lineDashOffset")}} property ([Firefox bug 768067](https://bugzil.la/768067)).
- The `typeMustMatch` attribute has been implemented on the {{domxref("HTMLObjectElement")}} interface ([Firefox bug 827160](https://bugzil.la/827160)).
- The `copyFromChannel()` and `copyToChannel()` methods have been added to {{domxref("AudioBuffer")}} ([Firefox bug 915524](https://bugzil.la/915524)).
- `Event.isTrusted()` is now unforgeable ([Firefox bug 637248](https://bugzil.la/637248)).
- The WebRTC API's {{domxref("RTCIceCandidate")}} object now includes a {{domxref("RTCIceCandidate.toJSON", "toJSON()")}} method to help with signaling and debugging ([Firefox bug 928304](https://bugzil.la/928304)).
- The {{domxref("Navigator.vibrate()")}} method has been adapted to match the final specification: It now returns `false` when the list is too long or has too large entries, instead of throwing ([Firefox bug 884935](https://bugzil.la/884935)).
- As part of the ongoing effort to standardize global objects, the non-standard stylesheet change event interfaces, including `StyleRuleChangeEvent`, `StyleSheetApplicableStateChangeEvent` and `StyleSheetChangeEvent`, are no longer available from Web content. The `CSSGroupRuleRuleList` interface, the implementation detail of {{domxref("CSSRuleList")}}, has also been removed ([Firefox bug 872934](https://bugzil.la/872934) and [Firefox bug 916871](https://bugzil.la/916871)).
- `atob` now ignores whitespaces ([Firefox bug 711180](https://bugzil.la/711180)).
- [WebGL](/en-US/docs/Web/API/WebGL_API): `MOZ_` prefixed extension strings are deprecated. Support for them will be removed in the future. Use unprefixed extension string only. To get draft extensions, set the `webgl.enable-draft-extensions` preferences ([Firefox bug 924176](https://bugzil.la/924176)).
### MathML
_No change._
### SVG
- Blending of SVG elements using the {{cssxref("mix-blend-mode")}} property has been implemented. The `layout.css.mix-blend-mode.enabled` preference must be set to `true` ([Firefox bug 902525](https://bugzil.la/902525)).
## Changes for addon and Mozilla developers
- The `downloads-indicator` button has gone away. You should now use the `downloads-button` element. If you need to check that it has loaded its overlay, check for the `indicator` attribute on that button.
- The `chrome://browser/skin/downloads/indicator.css` stylesheet is no longer referenced in Firefox.
## Security
- TLS 1.2 has been implemented for improved security ([Firefox bug 861266](https://bugzil.la/861266)).
## See also
- [List of changes](https://bugzilla.mozilla.org/buglist.cgi?resolution=FIXED&component=Marionette&product=Testing&target_milestone=mozilla27) in [Marionette](https://firefox-source-docs.mozilla.org/testing/marionette/index.html) for Firefox 27.
### Older versions
{{Firefox_for_developers('26')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/24/index.md | ---
title: Firefox 24 for developers
slug: Mozilla/Firefox/Releases/24
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
## Changes for Web developers
### CSS
- The two values `-moz-zoom-in` and `-moz-zoom-out` of the {{cssxref("cursor")}} property have been unprefixed to `zoom-in` and `zoom-out` ([Firefox bug 772153](https://bugzil.la/772153)).
- To match the specification, the keywords `not`, `only`, `and`, and `or` cannot be used as media types anymore ([Firefox bug 757554](https://bugzil.la/757554)).
### HTML
- The {{HTMLElement("track")}} element has been implemented behind the `media.webvtt.enabled` preference, and is disabled by default. ([Firefox bug 833385](https://bugzil.la/833385)).
### JavaScript
- [Arrow functions](/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions) are no longer automatically in strict mode unless explicitly requested with `"use strict"` ([Firefox bug 852762](https://bugzil.la/852762)).
- The [`String.prototype.repeat`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat) JS method has been implemented ([Firefox bug 815431](https://bugzil.la/815431)).
- The {{jsxref("Set.prototype.values()")}}, {{jsxref("Set/values", "Set.prototype.keys()")}} and {{jsxref("Set.prototype.entries()")}} methods on {{jsxref("Set")}} objects have been implemented ([Firefox bug 869996](https://bugzil.la/869996)).
### DOM
- Support for the {{domxref("Range.Range", "Range()")}} constructor has been added ([Firefox bug 868999](https://bugzil.la/868999)).
- Support for the {{domxref("Text.Text", "Text()")}} constructor has been added ([Firefox bug 869000](https://bugzil.la/869000)).
- Support for the {{domxref("Comment.Comment", "Comment()")}} constructor has been added ([Firefox bug 869006](https://bugzil.la/869006)).
- Support for the {{domxref("DocumentFragment.DocumentFragment", "DocumentFragment()")}} constructor has been added ([Firefox bug 869002](https://bugzil.la/869002)).
- The {{domxref("FocusEvent")}} interface has been implemented ([Firefox bug 855741](https://bugzil.la/855741)).
- Support for the {{domxref("Element.remove", "ChildNode.remove()")}} method has been added ([Firefox bug 856629](https://bugzil.la/856629)).
- The WebVTT interfaces related to the {{HTMLElement("track")}} element, {{domxref("HTMLTrackElement")}}, {{domxref("TextTrack")}}, {{domxref("TextTrackCue")}}, {{domxref("TextTrackList")}}, and {{domxref("TextTrackCueList")}} have been implemented behind the `media.webvtt.enabled` property, defaulting to `false` ([Firefox bug 833385](https://bugzil.la/833385)).
- The {{domxref("Gamepad")}} interface, and {{domxref("Navigator.getGamepads")}} have been implemented behind the `dom.gamepad.enabled` property, defaulting to `false` ([Firefox bug 690935](https://bugzil.la/690935)).
- On desktop Firefox only, `HTMLCanvasElement.getContext()` can now take the `webgl` value, in addition to `experimental-webgl` ([Firefox bug 870232](https://bugzil.la/870232)).
- The non-standard method `mozLoadFrom()` of {{domxref("HTMLMediaElement")}} has been removed ([Firefox bug 877135](https://bugzil.la/877135)).
### Developer Tools
- The Network inspector now lets you filter by content type (CSS/image/font etc.) and see the relevant size and load times.
- The Devtools options panel to the left lets you disable/enable JavaScript temporarily.
- Extension developers may use the new [Browser Console](https://mihai.sucan.ro/mihai/blog/the-browser-console-is-replacing-the-error-console) for Chrome-level scripts (Replaces Error Console).
- The source map syntax has been changed to use `//#` instead of `//@` ([Firefox bug 870361](https://bugzil.la/870361)).
### MathML
- The `dir` attribute for controlling directionality of formulas on e.g. {{MathMLElement("math")}} or {{MathMLElement("mrow")}} elements is now equivalent to using the {{cssxref("direction")}} CSS property.
- The equal sign ("=") is now [stretchable](/en-US/docs/Web/MathML/Element/mo#stretchy).
- The "`updiagonalarrow`" value for the `notation` attribute on {{MathMLElement("menclose")}} elements has been added.
## Changes for add-on and Mozilla developers
- Doc Shells have now the `allowMedia` attribute to disable media playing ([Firefox bug 759964](https://bugzil.la/759964)).
- Sherlock search plugins in the application directory or profile won't be loaded anymore ([Firefox bug 862143](https://bugzil.la/862143)).
## See also
- [Firefox 24 Aurora Notes](https://website-archive.mozilla.org/www.mozilla.org/firefox_releasenotes/en-us/firefox/24.0a2/auroranotes/)
## Older versions
{{Firefox_for_developers('23')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/78/index.md | ---
title: Firefox 78 for developers
slug: Mozilla/Firefox/Releases/78
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 78 that will affect developers. Firefox 78 was released on June 30, 2020.
See also [New in Firefox 78: DevTools improvements, new regex engine, and abundant web platform updates](https://hacks.mozilla.org/2020/06/new-in-firefox-78/) on Mozilla hacks.
## Changes for web developers
### Developer Tools
#### Debugger
- You can now change the URL accessed by the remote device from the [about:debugging](https://firefox-source-docs.mozilla.org/devtools-user/about_colon_debugging/index.html#connecting-to-a-remote-device) panel. ([Firefox bug 1617237](https://bugzil.la/1617237))
- The **Disable JavaScript** menu item in the [Debugger](https://firefox-source-docs.mozilla.org/devtools-user/debugger/ui_tour/index.html) now only affects the current tab, and is reset when the Developer Tools are closed. ([Firefox bug 1640318](https://bugzil.la/1640318))
- [Logpoints](https://firefox-source-docs.mozilla.org/devtools-user/debugger/set_a_logpoint/index.html) can map variable names in source-mapped code back to their original names, if you enable **Maps** in the [Scopes pane](https://firefox-source-docs.mozilla.org/devtools-user/debugger/ui_tour/index.html#scopes). ([Firefox bug 1536857](https://bugzil.la/1536857))
#### Network Monitor
- In the [Network Monitor](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_list/index.html#network-request-columns), you can now resize the columns of the request list by dragging the column borders anywhere in the table. ([Firefox bug 1618409](https://bugzil.la/1618409))
- The [request details panel](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_details/index.html) in the Network Monitor has some UX improvements. ([Firefox bug 1631302](https://bugzil.la/1631302), [Firefox bug 1631295](https://bugzil.la/1631295))
- If a request was blocked, the [request list](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_list/index.html) now shows the reason, such as an add-on, CSP, CORS, or Enhanced Tracking Protection. ([Firefox bug 1555057](https://bugzil.la/1555057), [Firefox bug 1445637](https://bugzil.la/1445637), [Firefox bug 1556451](https://bugzil.la/1556451))
#### Other tools
- The [Accessibility](https://firefox-source-docs.mozilla.org/devtools-user/accessibility_inspector/index.html) inspector is out of beta. You can use it to check for various accessibility issues on your site. ([Firefox bug 1602075](https://bugzil.la/1602075))
- Uncaught promise errors now provide all details in the Console, including their name and stack. ([Firefox bug 1636590](https://bugzil.la/1636590))
### CSS
- The {{CSSxRef(":is", ":is()")}} and {{CSSxRef(":where", ":where()")}} pseudo-classes are now enabled by default ([Firefox bug 1632646](https://bugzil.la/1632646)).
- The {{CSSxRef(":read-only")}} and {{CSSxRef(":read-write")}} pseudo-classes are now supported without prefixes ([Firefox bug 312971](https://bugzil.la/312971)).
- In addition, `:read-write` styles are no longer applied to disabled [`<input>`](/en-US/docs/Web/HTML/Element/input) and [`<textarea>`](/en-US/docs/Web/HTML/Element/textarea) elements, which was a violation of [the HTML spec](https://html.spec.whatwg.org/multipage/semantics-other.html#selector-read-write) ([Firefox bug 888884](https://bugzil.la/888884)).
### JavaScript
- The [`Intl.ListFormat`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/ListFormat) API is now supported ([Firefox bug 1589095](https://bugzil.la/1589095)).
- The [`Intl.NumberFormat()`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat) constructor has been extended to support new options specified in the [Intl.NumberFormat Unified API Proposal](https://github.com/tc39/proposal-unified-intl-numberformat) ([Firefox bug 1633836](https://bugzil.la/1633836)). This includes among other things:
- [Support for scientific notations](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat#scientific_engineering_or_compact_notations)
- [Unit](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat#unit_formatting), [currency](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat#currency_formatting) and [sign display](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat#displaying_signs) formatting
- The {{JSxRef("RegExp")}} engine [has been updated](https://hacks.mozilla.org/2020/06/a-new-regexp-engine-in-spidermonkey/) and now supports all new features introduced in ECMAScript 2018:
- [Lookbehind assertions](/en-US/docs/Web/JavaScript/Guide/Regular_expressions/Assertions) ([Firefox bug 1225665](https://bugzil.la/1225665))
- {{JSxRef("RegExp.prototype.dotAll")}} ([Firefox bug 1361856](https://bugzil.la/1361856))
- [Unicode property escapes](/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Unicode_character_class_escape) ([Firefox bug 1361876](https://bugzil.la/1361876))
- [Named capture groups](/en-US/docs/Web/JavaScript/Guide/Regular_expressions/Groups_and_backreferences) ([Firefox bug 1362154](https://bugzil.la/1362154))
- Due to a [WebIDL spec change](https://github.com/whatwg/webidl/pull/357) in mid-2020, we've [added a `Symbol.toStringTag` property to all DOM prototype objects](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/toStringTag#tostringtag_available_on_all_dom_prototype_objects) ([Firefox bug 1277799](https://bugzil.la/1277799)).
- The garbage collection of {{jsxref("WeakMap")}} objects has been improved. `WeakMaps` are now marked incrementally ([Firefox bug 1167452](https://bugzil.la/1167452)).
### APIs
#### DOM
- The {{DOMxRef("Element.replaceChildren")}} method has been implemented ([Firefox bug 1626015](https://bugzil.la/1626015)).
#### Service workers
- [Extended Support Releases (ESR)](https://www.mozilla.org/en-US/firefox/enterprise/): Firefox 78 is the first ESR release that supports [Service workers](/en-US/docs/Web/API/Service_Worker_API) (and the [Push API](/en-US/docs/Web/API/Push_API)). Earlier ESR releases had no support ([Firefox bug 1547023](https://bugzil.la/1547023)).
### WebAssembly
- [Wasm Multi-value](https://hacks.mozilla.org/2019/11/multi-value-all-the-wasm/) is now supported, meaning that WebAssembly functions can now return multiple values, and instruction sequences can consume and produce multiple stack values ([Firefox bug 1628321](https://bugzil.la/1628321)).
- WebAssembly now supports import and export of 64-bit integer function parameters (i64) using [`BigInt`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt) from JavaScript ([Firefox bug 1608770](https://bugzil.la/1608770)).
### TLS 1.0 and 1.1 removal
- Support for the [Transport Layer Security](/en-US/docs/Web/Security/Transport_Layer_Security) (TLS) protocol's version 1.0 and 1.1, is dropped from all browsers. Read [TLS 1.0 and 1.1 Removal Update](https://hacks.mozilla.org/2019/05/tls-1-0-and-1-1-removal-update/) for the previous announcement and what actions to take if you are affected ([Firefox bug 1643229](https://bugzil.la/1643229)).
## Changes for add-on developers
- {{WebExtAPIRef("browsingData.removeCache")}} and {{WebExtAPIRef("browsingData.removePluginData")}} now support deleting by hostname. ([Firefox bug 1636784](https://bugzil.la/1636784)).
- When using [`proxy.onRequest`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/proxy/onRequest), a filter that limits based on tab id or window id is now correctly applied. This could be useful for add-ons that want to provide proxy functionality just in just one window.
- [Clicking within the context menu](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/menus/onClicked) from the "all tabs" dropdown now passed the appropriate tab object. In the past, the active tab was erroneously passed.
- When using [`downloads.download`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/downloads/download) with the saveAs option, the recently used directory is now remembered. While this information is not available to developers, it is very convenient to users.
## Older versions
{{Firefox_for_developers(77)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/35/index.md | ---
title: Firefox 35 for developers
slug: Mozilla/Firefox/Releases/35
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
Firefox 35 was released on January 13th, 2015. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.
## Changes for Web developers
### Developer Tools
Highlights:
- [See ::before and ::after pseudo elements in the Page Inspector](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/index.html#.3a.3abefore-and-.3a.3aafter)
- [CSS source maps are now enabled by default](https://firefox-source-docs.mozilla.org/devtools-user/style_editor/index.html#source-map-support)
- ["Show DOM Properties" from the Page Inspector](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/index.html#element-popup-menu-2)
[All devtools bugs fixed between Firefox 34 and Firefox 35](https://bugzilla.mozilla.org/buglist.cgi?resolution=FIXED&chfieldto=2014-10-13&chfield=resolution&query_format=advanced&chfieldfrom=2014-09-02&chfieldvalue=FIXED&component=Developer%20Tools&component=Developer%20Tools%3A%203D%20View&component=Developer%20Tools%3A%20Canvas%20Debugger&component=Developer%20Tools%3A%20Console&component=Developer%20Tools%3A%20Debugger&component=Developer%20Tools%3A%20Framework&component=Developer%20Tools%3A%20Graphic%20Commandline%20and%20Toolbar&component=Developer%20Tools%3A%20Inspector&component=Developer%20Tools%3A%20Memory&component=Developer%20Tools%3A%20Netmonitor&component=Developer%20Tools%3A%20Object%20Inspector&component=Developer%20Tools%3A%20Profiler&component=Developer%20Tools%3A%20Responsive%20Mode&component=Developer%20Tools%3A%20Scratchpad&component=Developer%20Tools%3A%20Source%20Editor&component=Developer%20Tools%3A%20Storage%20Inspector&component=Developer%20Tools%3A%20Style%20Editor&component=Developer%20Tools%3A%20Timeline&component=Developer%20Tools%3A%20User%20Stories&component=Developer%20Tools%3A%20Web%20Audio%20Editor&component=Developer%20Tools%3A%20WebGL%20Shader%20Editor&component=Developer%20Tools%3A%20WebIDE&component=Simulator&product=Firefox&product=Firefox%20OS&list_id=11184176).
### CSS
- The {{cssxref("mask-type")}} property has been activated by default ([Firefox bug 1058519](https://bugzil.la/1058519)).
- The {{cssxref("filter")}} property is now activated by default ([Firefox bug 1057180](https://bugzil.la/1057180)).
- The {{cssxref("@font-face")}} at-rule now supports WOFF2 fonts ([Firefox bug 1064737](https://bugzil.la/1064737)).
- The {{cssxref("symbols", "symbols()")}} functional notation is now supported ([Firefox bug 966168](https://bugzil.la/966168)).
- The CSS Font Loading API has been implemented ([Firefox bug 1028497](https://bugzil.la/1028497)).
- Using `-moz-appearance` with the `none` value on a combobox now remove the dropdown button ([Firefox bug 649849](https://bugzil.la/649849)).
- The property accessor `element.style["css-property-name"]` has been added to match other browsers ([Firefox bug 958887](https://bugzil.la/958887)).
### HTML
- The obsolete and non-conforming `bottommargin`, `leftmargin`, `rightmargin` and `topmargin` attributes of the {{HTMLElement("body")}} element have been activated in non-quirks mode ([Firefox bug 95530](https://bugzil.la/95530)).
### JavaScript
- The "[temporal dead zone](/en-US/docs/Web/JavaScript/Reference/Statements/let#temporal_dead_zone_tdz)" for [`let`](/en-US/docs/Web/JavaScript/Reference/Statements/let) declarations has been implemented. In conformance with ES2015 `let` semantics, the following situations now throw errors. See also this [newsgroup announcement](https://groups.google.com/forum/#!topic/mozilla.dev.platform/tezdW299Zds) and [Firefox bug 1001090](https://bugzil.la/1001090).
- Redeclaring existing variables or arguments using `let` within the same scope in function bodies is now a syntax error.
- Using a variable declared using `let` in function bodies before the declaration is reached and evaluated is now a runtime error.
- ES2015 {{jsxref("Global_Objects/Symbol", "Symbols")}} (only available in the Nightly channel) have been updated to conform with recent specification changes:
- `String(Symbol("1"))` now no longer throws a {{jsxref("TypeError")}}; instead a string (`"Symbol(1)"`) gets returned ([Firefox bug 1058396](https://bugzil.la/1058396)).
- The various [_TypedArray_ constructors](/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray#typedarray_objects) now have as their `[[Prototype]]` a single function, denoted `%TypedArray%` in ES2015 (but otherwise not directly exposed). Each typed array prototype now inherits from `%TypedArray%.prototype`. (`%TypedArray%` and `%TypedArray%.prototype` inherit from [`Function.prototype`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function) and [`Object.prototype`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object), respectively, so that typed array constructors and instances still have the properties found on those objects.) Typed array function properties now reside on `%TypedArray%.prototype` and work on any typed array. See [_TypedArray_](/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray#description) and [Firefox bug 896116](https://bugzil.la/896116) for more information.
- ES2015 semantics for [prototype mutations using object literals](/en-US/docs/Web/JavaScript/Reference/Operators/Object_initializer) have been implemented ([Firefox bug 1061853](https://bugzil.la/1061853)).
- Now only a single member notated as `__proto__:value` will mutate the `[[Prototype]]` in the object literal syntax.
- Method members like `__proto__() {}` will not overwrite the `[[Prototype]]` anymore.
### Interfaces/APIs/DOM
- {{domxref("WorkerNavigator.language", "navigator.language")}} and {{domxref("WorkerNavigator.languages", "navigator.languages")}} are now available to workers on {{domxref("WorkerNavigator")}} ([Firefox bug 925849](https://bugzil.la/925849)).
- The {{domxref("Element.closest()")}} method returns the closest ancestor of the current element ([Firefox bug 1055533](https://bugzil.la/1055533)).
- Experimental support for the {{domxref("CanvasRenderingContext2D.filter")}} property has been added behind the `canvas.filters.enabled` flag ([Firefox bug 927892](https://bugzil.la/927892)).
- Our experimental implementation of Web Animations progresses with the landing of the `Animation.target` property. This always is behind the `dom.animations-api.core.enabled` pref, off by default ([Firefox bug 1067701](https://bugzil.la/1067701)).
- The {{domxref("Element.hasAttributes", "hasAttributes()")}} method has been moved from {{domxref("Node")}} to {{domxref("Element")}} as required by the spec ([Firefox bug 1055773](https://bugzil.la/1055773)).
- The `crossOrigin` reflected attribute of {{domxref("HTMLImageElement")}}, {{domxref("HTMLLinkElement")}}, {{domxref("HTMLMediaElement")}}, {{domxref("HTMLScriptElement")}}, and {{domxref("SVGScriptElement")}} only accepts valid values, and `""` isn't, `null` has to be used instead ([Firefox bug 880997](https://bugzil.la/880997)).
- The Resource Timing API has been activated by default ([Firefox bug 1002855](https://bugzil.la/1002855)).
- To match the spec, the first argument of {{domxref("Selection.containsNode()")}} cannot be `null` anymore ([Firefox bug 1068058](https://bugzil.la/1068058)).
- The new {{domxref("ImageCapture")}} API has been implemented: {{domxref("ImageCapture.takePhoto()")}} is available ([Firefox bug 916643](https://bugzil.la/916643)).
- Non-HTTP {{domxref("XMLHttpRequest")}} requests now return `200` in case of success (instead of the erroneous `0`) ([Firefox bug 716491](https://bugzil.la/716491)).
- {{domxref("XMLHttpRequest.responseURL")}} has been adapted to the latest spec and doesn't include the fragment (`'#xyz'`) of the URL, if relevant ([Firefox bug 1073882](https://bugzil.la/1073882)).
- The internal, non-standard, `File.mozFullPath` property is no more visible from content ([Firefox bug 1048293](https://bugzil.la/1048293)).
- The constructor of {{domxref("File")}} has been extended to match the specification ([Firefox bug 1047483](https://bugzil.la/1047483)).
- An experimental implementation of `AbortablePromise`, a promise that can be aborted by a different entity that the one who created it, has been added. It is prefixed with `Moz` and controlled by the `dom.abortablepromise.enabled` property, defaulting to `false` ([Firefox bug 1035060](https://bugzil.la/1035060)).
- The non-standard `Navigator.mozIsLocallyAvailable` property has been removed ([Firefox bug 1066826](https://bugzil.la/1066826)).
- The preference `network.websocket.enabled`, `true` by default, has been removed; [Websocket](/en-US/docs/Web/API/WebSockets_API) API cannot be deactivated anymore ([Firefox bug 1091016](https://bugzil.la/1091016)).
- The non-standard methods and properties of {{domxref("Crypto")}} have been removed ([Firefox bug 1030963](https://bugzil.la/1030963)). Only methods and properties defined in the standard WebCrypto API are left.
- Our experimental implementation of WebGL 2.0 is going forward!
- The {{domxref("WebGL2RenderingContext.copyBufferSubData()")}} method has been implemented ([Firefox bug 1048668](https://bugzil.la/1048668)).
### MathML
- The `dtls` OpenType feature (via the CSS {{cssxref("font-feature-settings")}} on the default stylesheet) is now applied automatically to MathML elements when positioning scripts over it (e.g. dotless i with mathematical hat).
### SVG
_No change._
### Audio/Video
_No change._
## Network & Security
- HTTP/2 has been implemented and activated, with AEAD ciphers only ([Firefox bug 1027720](https://bugzil.la/1027720) and [Firefox bug 1047594](https://bugzil.la/1047594)).
- The HTTP/2 `alt-svc` header is now supported ([Firefox bug 1003448](https://bugzil.la/1003448)).
- The Public Key Pinning Extension for HTTP (HPKP) has been implemented ([Firefox bug 787133](https://bugzil.la/787133)).
- The [CSP](/en-US/docs/Web/HTTP/CSP) 1.1 `base-uri` [directive](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy) is now supported ([Firefox bug 1045897](https://bugzil.la/1045897)).
- Path of the source is now considered too when host-source matching happens in [CSP](/en-US/docs/Web/HTTP/CSP) ([Firefox bug 808292](https://bugzil.la/808292)).
## Changes for add-on and Mozilla developers
### XUL & Add-ons
- The private `_getTabForBrowser()` method on the `<xul:tabbrowser>` element has been deprecated. In its place, we've added a new, public, method called `getTabForBrowser`. This returns, predictably, the `<xul:tab>` element that contains the specified `<xul:browser>`.
- `Components.utils.now()`, matching {{domxref("Performance.now()")}} has been implemented for non-window chrome code ([Firefox bug 969490](https://bugzil.la/969490)).
### Add-on SDK
#### Highlights
- Added access keys for context menu.
- Removed `isPrivateBrowsing` from `BrowserWindow`.
- Added `toJSON` method to `URL` instances.
#### Details
[GitHub commits made between Firefox 34 and Firefox 35](https://github.com/mozilla/addon-sdk/compare/firefox34...firefox35). This will not include any uplifts made after this release entered Aurora.
[Bugs fixed between Firefox 34 and Firefox 35](https://bugzilla.mozilla.org/buglist.cgi?resolution=FIXED&chfieldto=2014-10-13&chfield=resolution&query_format=advanced&chfieldfrom=2014-09-02&chfieldvalue=FIXED&bug_status=RESOLVED&bug_status=VERIFIED&bug_status=CLOSED&product=Add-on%20SDK&list_id=11562840). This will not include any uplifts made after this release entered Aurora.
## Older versions
{{Firefox_for_developers('34')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/51/index.md | ---
title: Firefox 51 for developers
slug: Mozilla/Firefox/Releases/51
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
[To test the latest developer features of Firefox, install Firefox Developer Edition](https://www.mozilla.org/firefox/developer/)Firefox 51 was released on January 24, 2017. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.
## Changes for Web developers
### HTML
- {{HTMLElement("hr")}} elements can now be used as separators in {{HTMLElement("menu")}} elements ([Firefox bug 870388](https://bugzil.la/870388)).
- The {{HTMLElement("input")}} and {{HTMLElement("textarea")}} elements' `selectionStart` and `selectionEnd` attributes now correctly return the current position of the text input cursor when there's no selection, instead of returning 0 ([Firefox bug 1287655](https://bugzil.la/1287655)).
### CSS
- Implemented {{cssxref(":indeterminate")}} for \<input type="radio"> ([Firefox bug 885359](https://bugzil.la/885359)).
- Implemented {{cssxref(":placeholder-shown")}} for `<input type="text">` ([Firefox bug 1069015](https://bugzil.la/1069015)).
- The {{cssxref("::placeholder")}} pseudo-element is now unprefixed ([Firefox bug 1069012](https://bugzil.la/1069012)).
- Fixed the {{cssxref(":valid")}} CSS pseudo-class which didn't match valid {{HTMLElement("form")}} elements ([Firefox bug 1285425](https://bugzil.la/1285425)).
- The `plaintext` value of {{cssxref("unicode-bidi")}} now also works with vertical writing modes ([Firefox bug 1302734](https://bugzil.la/1302734)).
- The `fill-box` and `stroke-box` values of {{cssxref("clip-path")}} are now properly supported; previously, they were aliases of `border-box` ([Firefox bug 1289011](https://bugzil.la/1289011)).
- Clamp flex line's height (clamping stretched flex items), in single-line auto-height flex container w/ max-height (spec change) ([Firefox bug 1000957](https://bugzil.la/1000957)).
### JavaScript
- The ES2015 {{jsxref("Symbol.toStringTag")}} property has been implemented ([Firefox bug 1114580](https://bugzil.la/1114580)).
- The ES2015 {{jsxref("TypedArray.prototype.toString()")}} and {{jsxref("TypedArray.prototype.toLocaleString()")}} methods have been implemented ([Firefox bug 1121938](https://bugzil.la/1121938)).
- The {{jsxref("Intl/DateTimeFormat/formatToParts", "DateTimeFormat.prototype.formatToParts()")}} method is now available ([Firefox bug 1289340](https://bugzil.la/1289340)).
- {{jsxref("Statements/const", "const")}} and {{jsxref("Statements/let", "let")}} are now fully ES2015-compliant ([Firefox bug 950547](https://bugzil.la/950547)).
- Using {{jsxref("Statements/const", "const")}} in [`for...of`](/en-US/docs/Web/JavaScript/Reference/Statements/for...of) loops now has a fresh binding for each iteration and no longer throws a {{jsxref("SyntaxError")}} ([Firefox bug 1101653](https://bugzil.la/1101653)).
- The deprecated [for each...in](/en-US/docs/Web/JavaScript/Reference/Statements/for_each...in) loop now presents a [warning in the console](/en-US/docs/Web/JavaScript/Reference/Errors/For-each-in_loops_are_deprecated) ([Firefox bug 1293205](https://bugzil.la/1293205)). Please migrate your code to use the standardized [`for...of`](/en-US/docs/Web/JavaScript/Reference/Statements/for...of) loop.
- [Generator functions](/en-US/docs/Web/JavaScript/Reference/Statements/function*) can't have a [label](/en-US/docs/Web/JavaScript/Reference/Statements/label) anymore and "`let`" as a label name is disallowed now ([Firefox bug 1288459](https://bugzil.la/1288459)).
- Deprecated [legacy generator functions](/en-US/docs/Web/JavaScript/Reference/Deprecated_and_obsolete_features) will now throw when used in [method definitions](/en-US/docs/Web/JavaScript/Reference/Functions/Method_definitions) ([Firefox bug 1199296](https://bugzil.la/1199296)).
- The `next()` method of the [iterator protocol](/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#the_iterator_protocol) will now throw a {{jsxref("TypeError")}} if the returned value is not an object ([Firefox bug 1016936](https://bugzil.la/1016936)).
- Child-indexed pseudo-class selectors should match without a parent ([Firefox bug 1300374](https://bugzil.la/1300374)).
### Developer Tools
- [Network Monitor now shows a "Blocked" state for network requests.](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/index.html#timings)
- [All devtools bugs fixed between Firefox 50 and Firefox 51](https://bugzilla.mozilla.org/buglist.cgi?list_id=13263768&resolution=FIXED&classification=Client%20Software&chfieldto=2016-09-19&query_format=advanced&chfield=resolution&chfieldfrom=2016-08-01&chfieldvalue=FIXED&bug_status=RESOLVED&bug_status=VERIFIED&component=Developer%20Tools&component=Developer%20Tools%3A%20about%3Adebugging&component=Developer%20Tools%3A%20Animation%20Inspector&component=Developer%20Tools%3A%20Canvas%20Debugger&component=Developer%20Tools%3A%20Computed%20Styles%20Inspector&component=Developer%20Tools%3A%20Console&component=Developer%20Tools%3A%20CSS%20Rules%20Inspector&component=Developer%20Tools%3A%20Debugger&component=Developer%20Tools%3A%20DOM&component=Developer%20Tools%3A%20Font%20Inspector&component=Developer%20Tools%3A%20Framework&component=Developer%20Tools%3A%20Graphic%20Commandline%20and%20Toolbar&component=Developer%20Tools%3A%20Inspector&component=Developer%20Tools%3A%20JSON%20Viewer&component=Developer%20Tools%3A%20Memory&component=Developer%20Tools%3A%20Netmonitor&component=Developer%20Tools%3A%20Object%20Inspector&component=Developer%20Tools%3A%20Performance%20Tools%20%28Profiler%2FTimeline%29&component=Developer%20Tools%3A%20Responsive%20Design%20Mode&component=Developer%20Tools%3A%20Scratchpad&component=Developer%20Tools%3A%20Shared%20Components&component=Developer%20Tools%3A%20Source%20Editor&component=Developer%20Tools%3A%20Storage%20Inspector&component=Developer%20Tools%3A%20Style%20Editor&component=Developer%20Tools%3A%20User%20Stories&component=Developer%20Tools%3A%20Web%20Audio%20Editor&component=Developer%20Tools%3A%20WebGL%20Shader%20Editor&component=Developer%20Tools%3A%20WebIDE&product=Firefox).
### WebGL
- [WebGL 2](/en-US/docs/Web/API/WebGL_API) is now enabled by default. See [webglsamples.org/WebGL2Samples](https://webglsamples.org/WebGL2Samples/) for a few demos.
- WebGL 2 provides the {{domxref("WebGL2RenderingContext")}} interface that brings OpenGL ES 3.0 to the {{HTMLElement("canvas")}} element.
- New features include:
- [3D textures](/en-US/docs/Web/API/WebGL2RenderingContext/texImage3D),
- [Sampler objects](/en-US/docs/Web/API/WebGLSampler),
- [Uniform Buffer objects](/en-US/docs/Web/API/WebGL2RenderingContext#uniform_buffer_objects),
- [Sync objects](/en-US/docs/Web/API/WebGLSync),
- [Query objects](/en-US/docs/Web/API/WebGLQuery),
- [Transform Feedback objects](/en-US/docs/Web/API/WebGLTransformFeedback),
- Promoted extensions that are now core to WebGL 2: [Vertex Array objects](/en-US/docs/Web/API/WebGLVertexArrayObject), [instancing](/en-US/docs/Web/API/WebGL2RenderingContext/drawArraysInstanced), [multiple render targets](/en-US/docs/Web/API/WebGL2RenderingContext/drawBuffers), [fragment depth](/en-US/docs/Web/API/EXT_frag_depth).
- The `WEBGL_compressed_texture_es3` extension (implemented in Firefox 46) has been renamed to {{domxref("WEBGL_compressed_texture_etc")}} ([Firefox bug 1316778](https://bugzil.la/1316778)) and is no longer included by default in WebGL 2 contexts ([Firefox bug 1306174](https://bugzil.la/1306174)).
- The {{domxref("EXT_disjoint_timer_query")}} extension has been updated to use {{domxref("WebGLQuery")}} objects instead of `WebGLTimerQuery` objects ([Firefox bug 1308057](https://bugzil.la/1308057)).
- The {{domxref("OES_vertex_array_object")}} extension now uses the WebGL 2 {{domxref("WebGLVertexArrayObject")}} object instead of its own `WebGLVertexArrayObjectOES` object ([Firefox bug 1318523](https://bugzil.la/1318523)).
- You can now use {{domxref("ImageBitmap")}} objects as a sources for texture images in methods like {{domxref("WebGLRenderingContext.texImage2D()")}}, {{domxref("WebGLRenderingContext.texSubImage2D()")}}, {{domxref("WebGL2RenderingContext.texImage3D()")}}, or {{domxref("WebGL2RenderingContext.texSubImage3D()")}} ([Firefox bug 1324924](https://bugzil.la/1324924)).
### IndexedDB v2
- [IndexedDB](/en-US/docs/Web/API/IndexedDB_API) version 2 implementation is now complete:
- Supports for the new {{domxref("IDBObjectStore.getKey()")}} method has been added ([Firefox bug 1271506](https://bugzil.la/1271506)).
- Supports for {{domxref("IDBCursor.continuePrimaryKey()")}} method has been added ([Firefox bug 1271505](https://bugzil.la/1271505)).
- Binary keys are now supported ([Firefox bug 1271500](https://bugzil.la/1271500)).
- See also ["What's new in IndexedDB 2.0?" – Mozilla hacks](https://hacks.mozilla.org/2016/10/whats-new-in-indexeddb-2-0/)
### Canvas
- The non-standard `CanvasRenderingContext2D.mozFillRule()` method has been removed; the fill rule can be defined using a parameter of the standard {{domxref("CanvasRenderingContext2D.fill()")}} method ([Firefox bug 826619](https://bugzil.la/826619)).
- The {{domxref("CanvasRenderingContext2D.imageSmoothingEnabled")}} has been unprefixed ([Firefox bug 768072](https://bugzil.la/768072))
### SVG
- Added {{SVGAttr("tabindex")}} attribute ([Firefox bug 778654](https://bugzil.la/778654)).
- Added {{SVGAttr("href")}} attribute, which renders {{SVGAttr("xlink:href")}} obsolete ([Firefox bug 1245751](https://bugzil.la/1245751)).
- You can now use custom data attributes on SVG elements through the {{domxref("HTMLElement.dataset")}} property and the {{SVGAttr("data-*")}} set of SVG attributes ([Firefox bug 921834](https://bugzil.la/921834)).
- CSS Animations used in an SVG image which is presented in an {{HTMLElement("img")}} element now work again; this was an old regression ([Firefox bug 1190881](https://bugzil.la/1190881)).
### Web Workers
- The non-standard and obsolete {{domxref("DedicatedWorkerGlobalScope.close")}} event handler and {{domxref("Worker")}} use of the `close` event have been removed from Firefox.
### Networking
- Scripts served with an `image/*`, `video/*`, `audio/*` or `text/csv` MIME type are now blocked and are not loaded or executed. This happen when they are declared using {{HTMLElement("script")}}, or loaded via {{domxref("Worker.importScripts()")}}, {{domxref("Worker.Worker","Worker()")}}, {{domxref("SharedWorker.SharedWorker", "SharedWorker()")}} ([Firefox bug 1229267](https://bugzil.la/1229267) and [Firefox bug 1288361](https://bugzil.la/1288361)).
- Support for SHA-1 certificates from publicly-trusted certificate authorities has been removed ([Firefox bug 1302140](https://bugzil.la/1302140)). See also [Phasing Out SHA-1 on the Public Web](https://blog.mozilla.org/security/2016/10/18/phasing-out-sha-1-on-the-public-web/) for more information.
- New WoSign and StartCom certificates will no longer be accepted ([Firefox bug 1309707](https://bugzil.la/1309707)), see [Distrusting New WoSign and StartCom Certificates](https://blog.mozilla.org/security/2016/10/24/distrusting-new-wosign-and-startcom-certificates/) for more information.
- The [PAC](</en-US/docs/Mozilla/Projects/Necko/Proxy_Auto-Configuration_(PAC)_file>) `FindProxyForURL(url, host)` function now strips paths and queries from https\:// URLs to avoid information leakage (see [Firefox bug 1255474](https://bugzil.la/1255474), [Sniffing HTTPS URLS with malicious PAC files](https://www.contextis.com/us/blog/leaking-https-urls-20-year-old-vulnerability), or `CVE-2017-5384`).
### XHR
- The {{domxref("XMLHttpRequest.responseXML")}} property no longer returns a partial {{domxref("Document")}} with a \<parsererror> node placed at the top when a parse error occurs attempting to interpret the received data. Instead, it correctly returns `null` ([Firefox bug 289714](https://bugzil.la/289714)).
- To match the latest specification an {{domxref("XMLHttpRequest")}} without an {{HTTPHeader("Accept")}} header set with {{domxref("XMLHttpRequest.setRequestHeader()", "setRequestHeader()")}} is now sent with such a header, with its value set to `*/*` ([Firefox bug 918752](https://bugzil.la/918752)).
- Fixed {{domxref("XMLHttpRequest.open()")}} so that, when omitted, the `username` and `password` parameters now default to `null`, per the specification ([Firefox bug 933759](https://bugzil.la/933759)).
### WebRTC
- The {{domxref("RTCPeerConnection.removeStream()")}} method has been removed. It was deprecated back in Firefox 22, and has been throwing a `NotSupportedError` {{domxref("DOMException")}} for a long time. You need to use {{domxref("RTCPeerConnection.removeTrack()")}} instead, for each track on the stream.
- WebRTC now supports the VP9 codec by default. When added in Firefox 46, VP9 was disabled by default, but when enabled was the preferred codec; however, it has been moved to be the second choice (after VP8) due to its current level of CPU usage.
- The method {{domxref("HTMLMediaElement.captureStream()")}}, which returns a {{domxref("MediaStream")}} containing the content of the specified {{HTMLElement("video")}} or {{HTMLElement("audio")}}. It's worth noting that this is prefixed still as `mozCaptureStream()`, and that it doesn't yet exactly match the spec.
### Audio/video
- Added FLAC support ([FLAC codec](https://xiph.org/flac/index.html)) in both FLAC and Ogg containers ([Firefox bug 1195723](https://bugzil.la/1195723)). Supported FLAC MIME types are: `audio/flac` and `audio/x-flac`. For FLAC in Ogg, supported MIME types are: `audio/ogg; codecs=flac`, and `video/ogg; codecs=flac`.
- Added support for FLAC in MP4 (both with and without MSE) ([Firefox bug 1303888](https://bugzil.la/1303888)).
- Throttling in background tabs of timers created by {{domxref("setInterval()")}} and {{domxref("setTimeout()")}} was changed in Firefox 50 to no longer occur if a [Web Audio API](/en-US/docs/Web/API/Web_Audio_API) {{domxref("AudioContext")}} is actively playing sound. However, this didn't resolve all scenarios in which timing-sensitive audio playback (such as music players generating individual notes using timers) could fail to work properly. For that reason, Firefox 51 no longer throttles background tabs which have an {{domxref("AudioContext")}}, even if it's not currently playing sound.
### DOM
- The {{domxref("DOMImplementation.hasFeature()")}} now returns `true` in all cases ([Firefox bug 984778](https://bugzil.la/984778)).
- The {{domxref("HTMLInputElement")}} and {{domxref("HTMLTextAreaElement")}} properties `selectionStart` and `selectionEnd` now correctly return the current position of the text input cursor when there's no selection, instead of returning 0 ([Firefox bug 1287655](https://bugzil.la/1287655)).
- The {{domxref("HTMLImageElement")}} interface and the corresponding {{HTMLElement("img")}} element now support the `onerror` event handler, sending {{domxref("HTMLElement/error_event", "error")}} events to the element whenever [errors occur attempting to load or interpret images](/en-US/docs/Web/API/HTMLImageElement#errors).
- You can now change a Web {{domxref("Animation")}}'s effect by setting the value of its {{domxref("Animation.effect", "effect")}} property. Previously, this property was read-only ([Firefox bug 1049975](https://bugzil.la/1049975)).
- The Permissions API method {{domxref("Permissions.revoke()")}} has been put behind a preference (`dom.permissions.revoke.enable`) and disabled by default since its design and even its very existence is under discussion in the [Web Application Security Working Group](https://www.w3.org/2011/webappsec/).
- The [Storage API](/en-US/docs/Web/API/Storage_API)'s {{domxref("Navigator.storage")}} property and {{domxref("StorageManager.estimate()")}} method have been implemented along with the needed supporting code. Storage unit persistence features are not yet implemented. See [Firefox bug 1267941](https://bugzil.la/1267941).
- For privacy reasons, both {{domxref("BatteryManager.chargingTime")}} and {{domxref("BatteryManager.dischargingTime")}} now round the returned value to the closest 15 minutes ([Firefox bug 1292655](https://bugzil.la/1292655)).
### Events
- Firefox now supports the {{domxref("Element.onanimationstart", "onanimationstart")}}, {{domxref("Element.onanimationiteration", "onanimationiteration")}}, and {{domxref("Element.onanimationstart", "onanimationstart")}} event handlers, in addition to supporting the corresponding events using {{domxref("EventTarget.addEventListener", "addEventListener()")}} ([Firefox bug 911987](https://bugzil.la/911987)).
- Firefox now supports the {{domxref("Element.transitionend_event", "ontransitionend")}} event handler ([Firefox bug 911987](https://bugzil.la/911987)).
### Security
- When login pages (i.e., those containing an [`<input type="password">`](/en-US/docs/Web/HTML/Element/input/password) field) are created so that they would be submitted insecurely, Firefox displays a crossed-out lock icon in the address bar to warn users ([Firefox bug 1319119](https://bugzil.la/1319119)). See [Insecure passwords](/en-US/docs/Web/Security/Insecure_passwords) for more details.
### Removals
- The non-standard [Simple Push API](/en-US/docs/Archive/Firefox_OS/API/Simple_Push_API), mainly intended for use with Firefox OS and now superseded by the [W3C Push API](/en-US/docs/Web/API/Push_API), has been completely removed from Gecko ([Firefox bug 1296579](https://bugzil.la/1296579)).
- The non-standard [Alarms API](/en-US/docs/Archive/Firefox_OS/API/Alarm_API), mainly intended for use with Firefox OS, has been completely removed from Gecko ([Firefox bug 1300884](https://bugzil.la/1300884)).
- Support for prefixes in the [Page Visibility API](/en-US/docs/Web/API/Page_Visibility_API) has been removed ([Firefox bug 812701](https://bugzil.la/812701)).
## Changes for add-on and Mozilla developers
### WebExtensions
- New APIs:
- {{WebExtAPIRef("idle.queryState()")}} ([Firefox bug 1299846](https://bugzil.la/1299846))
- {{WebExtAPIRef("idle.onStateChanged")}} ([Firefox bug 1299775](https://bugzil.la/1299775))
- {{WebExtAPIRef("management.getSelf()")}} ([Firefox bug 1283116](https://bugzil.la/1283116))
- {{WebExtAPIRef("management.uninstallSelf()")}} ([Firefox bug 1220136](https://bugzil.la/1220136))
- {{WebExtAPIRef("runtime.getBrowserInfo()")}} ([Firefox bug 1268399](https://bugzil.la/1268399))
- {{WebExtAPIRef("runtime.reload()")}} and {{WebExtAPIRef("runtime.onUpdateAvailable()")}} ([Firefox bug 1279012](https://bugzil.la/1279012))
- You can now [embed a WebExtension in a legacy add-on type](/en-US/docs/Mozilla/Add-ons/WebExtensions/Embedded_WebExtensions) ([Firefox bug 1252215](https://bugzil.la/1252215)).
- [Clipboard access](/en-US/docs/Mozilla/Add-ons/WebExtensions/Interact_with_the_clipboard) is now supported ([Firefox bug 1197451](https://bugzil.la/1197451))
- The arguments passed to the callback of {{WebExtAPIRef("tabs.executeScript()")}} have been fixed ([Firefox bug 1290157](https://bugzil.la/1290157))
- [localStorage](/en-US/docs/Web/API/Window/localStorage) is now cleared when a WebExtension is uninstalled ([Firefox bug 1213990](https://bugzil.la/1213990))
- A changed {{HTTPHeader("Content-Type")}} header in Web Extensions is now taken into account ([Firefox bug 1304331](https://bugzil.la/1304331))
### Other
- The [`multiprocessCompatible` property of `install.rdf`](/en-US/docs/Mozilla/Add-ons/Install_Manifests#multiprocesscompatible) must now be explicitly set to `false` to prevent multiprocess from being enabled in Firefox when the add-on is installed.
- The Mozilla-specific [Social API](/en-US/docs/Mozilla/Projects/Social_API) has been substantially changed (largely to remove APIs no longer used), as follows:
- The {{domxref("MozSocial")}} interface and the {{domxref("navigator.mozSocial")}} property which supports it have been removed.
- The [Social Bookmarks API](/en-US/docs/Mozilla/Projects/Social_API/Bookmarks) has been removed.
- The Social chat functionality has been removed.
- The Social Status API has been removed.
- All of the [social widgets](/en-US/docs/Mozilla/Projects/Social_API/Widgets), except for the Share panel, have been removed. This includes the social sidebar, flyover panels, and so forth.
- All supporting user interface features and functionality for the removed APIs have been removed as well.
- [Social service provider manifest](/en-US/docs/Mozilla/Projects/Social_API/Manifest) properties supporting the removed functionality are no longer supported.
- If an add-on uses `mimeTypes.rdf` to provide a file extension to MIME type mapping, it must now register an entry in the `"ext-to-type-mapping"` category ([Firefox bug 306471](https://bugzil.la/306471)).
- The [Browser API](/en-US/docs/Mozilla/Gecko/Chrome/API/Browser_API) now includes a `detail` object on the event object of the [`mozbrowserlocationchange`](/en-US/docs/Web/Events/mozbrowserlocationchange) event that contains `canGoForward`/`canGoBack` properties, allowing retrieval of the mozBrowser's back/forward status synchronously ([Firefox bug 1279635](https://bugzil.la/1279635)).
## Older versions
{{Firefox_for_developers(50)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/62/index.md | ---
title: Firefox 62 for developers
slug: Mozilla/Firefox/Releases/62
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 62 that will affect developers. Firefox 62 was released on September 5, 2018.
## Changes for web developers
### Developer tools
- The Shape Path Editor is now available by default — see [Edit Shape Paths in CSS](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/edit_css_shapes/index.html) for more information.
- You can now split the Rules view out into its own pane, separate from the other tabs on the CSS pane. See [Page inspector 3-pane mode](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/3-pane_mode/index.html) for more details.
- The Grid inspector has updated features, and all new documentation — see [CSS Grid Inspector: Examine grid layouts](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_grid_layouts/index.html).
- You now have four options for the location of the Developer Tools. In addition to the default location on the bottom of the window, you can choose to locate the tools on either the left or right sides of the main window or in a separate window ([Firefox bug 1192642](https://bugzil.la/1192642)).
- A close button has been added to the [split console](https://firefox-source-docs.mozilla.org/devtools-user/web_console/split_console/index.html) toolbar.
- If the option to "Select an iframe as the currently targeted document" is checked, the icon will appear in the toolbar while the Settings tab is displayed, even if the current page doesn't include any iframes ([Firefox bug 1456069](https://bugzil.la/1456069)).
- The [Network Monitor](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/index.html)'s [Cookies tab](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/index.html#cookies) now shows the cookie `samesite` attribute ([Firefox bug 1452715](https://bugzil.la/1452715)).
- [Responsive design mode](https://firefox-source-docs.mozilla.org/devtools-user/responsive_design_mode/index.html) now works inside container tabs ([Firefox bug 1306975](https://bugzil.la/1306975)).
- When {{Glossary("CORS")}} errors occur and are reported on the console, Firefox now provides a link to the corresponding page in our [CORS error documentation](/en-US/docs/Web/HTTP/CORS/Errors) ([Firefox bug 1475391](https://bugzil.la/1475391)).
- Create a screenshot of the current page (with an optional filename) from the Console tab ([Firefox bug 1464461](https://bugzil.la/1464461)) using the following command:
```bash
:screenshot <filename.png> --fullpage
```
where `<filename.png>` is the desired filename. The file will be saved to your downloads folder. The `--fullpage` parameter is optional, but if included, it will save the full web page. This option also adds `-fullpage` to the name of the file. For a list of all options available for this command, enter: `:screenshot --help`
#### Removals
- The _Developer Toolbar/GCLI_ (accessed with `Shift` + `F2`), **has been removed** from Firefox ([Firefox bug 1461970](https://bugzil.la/1461970)). Both the Developer Toolbar UI and the GCLI upstream library have become unmaintained, some of its features are broken (some ever since e10s), it is blocking the `unsafeSetInnerHTML` work, usage numbers are very low, alternatives exist for the most used commands.
### HTML
_No changes._
### CSS
- `:-moz-selection` has been unprefixed to {{cssxref("::selection")}} ([Firefox bug 509958](https://bugzil.la/509958)).
- `x` is now supported as a unit for the {{cssxref("<resolution>")}} type ([Firefox bug 1460655](https://bugzil.la/1460655)).
- {{cssxref("shape-margin")}}, {{cssxref("shape-outside")}}, and {{cssxref("shape-image-threshold")}} are now enabled by default ([Firefox bug 1457297](https://bugzil.la/1457297)).
#### Removals
- All [XUL `display` values](/en-US/docs/Web/CSS/display#xul_values) with the exception of `-moz-box` and `-moz-inline-box` have been removed from non-XUL documents in [Firefox bug 1288572](https://bugzil.la/1288572).
### SVG
_No changes._
### JavaScript
- The [`WebAssembly.Global()`](/en-US/docs/WebAssembly/JavaScript_interface/Global) constructor is now supported, along with global variables in WebAssembly ([Firefox bug 1464656](https://bugzil.la/1464656)).
- The {{jsxref("Array.prototype.flat()")}} and {{jsxref("Array.prototype.flatMap()")}} methods are now enabled by default ([Firefox bug 1435813](https://bugzil.la/1435813)).
- The [`import.meta`](/en-US/docs/Web/JavaScript/Reference/Operators/import.meta) property has been implemented to expose context-specific metadata to a JavaScript module ([Firefox bug 1427610](https://bugzil.la/1427610)).
- JavaScript [string literals](/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#string_literals) may now directly contain the U+2028 LINE SEPARATOR and U+2029 PARAGRAPH SEPARATOR characters. As a consequence, {{jsxref("JSON")}} syntax is now a subset of JavaScript literal syntax (see [Firefox bug 1435828](https://bugzil.la/1435828) and the TC39 proposal [json-superset](https://github.com/tc39/proposal-json-superset)).
- For out-of-bounds [typed array](/en-US/docs/Web/JavaScript/Guide/Typed_arrays) indexes, {{jsxref("Reflect.defineProperty()")}} and {{jsxref("Reflect.set()")}} will now return `false` instead of `true` ([Firefox bug 1308735](https://bugzil.la/1308735)).
#### Removals
- The `DOMPoint` and `DOMPointReadOnly` constructors no longer support an input parameter of type `DOMPointInit`; the values of the properties must be specified using the `x`, `y`, `z`, and `w` parameters ([Firefox bug 1186265](https://bugzil.la/1186265)).
- The {{domxref("URL.createObjectURL_static", "URL.createObjectURL()")}} method no longer supports creating object URLs to represent a {{domxref("MediaStream")}}. This capability has been obsolete for some time, since you can now set {{domxref("HTMLMediaElement.srcObject")}} to the `MediaStream` directly ([Firefox bug 1454889](https://bugzil.la/1454889)).
### APIs
#### New APIs
- The {{domxref("Web_Speech_API", "Speech Synthesis API (Text-to-Speech)", "", "1")}} is now enabled by default on Firefox for Android ([Firefox bug 1463496](https://bugzil.la/1463496)).
#### DOM
- The {{domxref("DOMPointReadOnly")}} interface now supports the static function {{domxref("DOMPointReadOnly.fromPoint_static", "DOMPointReadOnly.fromPoint()")}}, which creates a new point object from a dictionary that's compatible with `DOMPointInit`, which includes any {{domxref("DOMPoint")}} object. This function is also available on {{domxref("DOMPoint")}} ([Firefox bug 1186265](https://bugzil.la/1186265)).
- For compatibility purposes, the {{domxref("Event.srcElement")}} property is now supported. It is an alias for {{domxref("Event.target")}} ([Firefox bug 453968](https://bugzil.la/453968)).
- {{domxref("Navigator.registerProtocolHandler()")}} now must only be called from a secure context ([Firefox bug 1460506](https://bugzil.la/1460506)).
- The {{domxref("Navigator.registerContentHandler()")}} method has been disabled by default in preparation for being removed entirely, as it's been obsolete for some time ([Firefox bug 1460481](https://bugzil.la/1460481)).
- The {{domxref("DataTransfer.DataTransfer", "DataTransfer()")}} constructor has been implemented ([Firefox bug 1351193](https://bugzil.la/1351193)).
- {{domxref("Document.domain")}} can no longer return `null` ([Firefox bug 819475](https://bugzil.la/819475)). If the domain cannot be identified, then `domain` returns an empty string instead of `null`.
- Added the {{domxref("console/timeLog_static", "console.timeLog()")}} method to display the current value of a console timer while continuing to track the time ([Firefox bug 1458466](https://bugzil.la/1458466)).
- Added {{domxref("console/countReset_static", "console.countReset()")}} to reset a console counter value ([Firefox bug 1459279](https://bugzil.la/1459279)).
#### DOM events
_No changes._
#### Service workers
_No changes._
#### Media, Web Audio, and WebRTC
- The `"media.autoplay.enabled"` preference now controls automatic playback of both audio and video media, instead of just video media ([Firefox bug 1413098](https://bugzil.la/1413098)).
- The {{domxref("ChannelSplitterNode")}} has been fixed to correctly default to having 6 channels with the `channelInterpretation` set to `"discrete"` and the `channelCountMode` set to `"explicit"`, as per the specification ([Firefox bug 1456265](https://bugzil.la/1456265)).
#### Removals
- The `userproximity` and `deviceproximity` events, as well as the `UserProximityEvent` and `DeviceProximityEvent` interfaces, have been disabled by default behind the `device.sensors.proximity.enabled` preference ([Firefox bug 1462308](https://bugzil.la/1462308)).
- The `devicelight` event of type `DeviceLightEvent` has been disabled by default behind the `device.sensors.ambientLight.enabled` preference ([Firefox bug 1462308](https://bugzil.la/1462308)).
- The `DOMSubtreeModified` and `DOMAttrModified` [mutation events](/en-US/docs/Web/API/MutationEvent) are no longer thrown when the [`style`](/en-US/docs/Web/HTML/Global_attributes#style) attribute is changed via the CSSOM ([Firefox bug 1460295](https://bugzil.la/1460295).
- Support for {{domxref("CSSStyleDeclaration.getPropertyCSSValue()")}} has been removed ([Firefox bug 1408301](https://bugzil.la/1408301)).
- Support for {{domxref("CSSValue")}}, {{domxref("CSSPrimitiveValue")}}, and {{domxref("CSSValueList")}} has been removed ([Firefox bug 1459871](https://bugzil.la/1459871)).
- {{domxref("window.getComputedStyle()")}} no longer returns `null` when called on a `Window` which has no presentation ([Firefox bug 1467722](https://bugzil.la/1467722)).
### HTTP
#### Removals
- The deprecated CSP {{CSP("referrer")}} directive has been removed. Please use the {{HTTPHeader("Referrer-Policy")}} header instead ([Firefox bug 1302449](https://bugzil.la/1302449)).
### Security
_No changes._
### Plugins
_No changes._
### WebDriver conformance (Marionette)
#### New features
- Command `WebDriver:ElementSendKeys` has been made WebDriver conforming for file uploads ([Firefox bug 1448792](https://bugzil.la/1448792)).
- User prompts as raised by `beforeunload` events are automatically dismissed for `WebDriver:Get`, `WebDriver:Back`, `WebDriver:Forward`, `WebDriver:Refresh`, and `WebDriver:Close` commands ([Firefox bug 1434872](https://bugzil.la/1434872)).
- `WebDriver:PerformActions` for `Ctrl` + `Click` synthesizes a {{domxref("Element/contextmenu_event", "contextmenu")}} event ([Firefox bug 1421323](https://bugzil.la/1421323)).
#### API changes
- Removed obsolete endpoints including `getWindowPosition`, `setWindowPosition`, `getWindowSize`, and `setWindowSize` ([Firefox bug 1348145](https://bugzil.la/1348145)).
- WebDriver commands which return success with data `null` now return an empty dictionary ([Firefox bug 1461463](https://bugzil.la/1461463)).
#### Bug fixes
- `WebDriver:ExecuteScript` caused cyclic reference error for [WebElement](/en-US/docs/Web/WebDriver/WebElement) collections ([Firefox bug 1447977](https://bugzil.la/1447977)).
- Dispatching a `pointerMove` or `pause` action primitive could cause a hang, and the command to never send a reply ([Firefox bug 1467743](https://bugzil.la/1467743), [Firefox bug 1447449](https://bugzil.la/1447449)).
### Other
_No changes._
## Changes for add-on developers
### API changes
- Added the {{WebExtAPIRef("webRequest.getSecurityInfo()")}} API to examine details of TLS connections ([Firefox bug 1322748](https://bugzil.la/1322748)).
- Added the {{WebExtAPIRef("browserSettings.newTabPosition")}} to customize where new tabs open ([Firefox bug 1344749](https://bugzil.la/1344749)).
- `windowTypes` has been deprecated in {{WebExtAPIRef("windows.get()")}}, {{WebExtAPIRef("windows.getCurrent()")}}, and {{WebExtAPIRef("windows.getLastFocused()")}} ([Firefox bug 1419132](https://bugzil.la/1419132)).
- It's now possible to modify a browser action on a per-window basis ([Firefox bug 1419893](https://bugzil.la/1419893)).
### Manifest changes
- New `open_at_install` property of the [`sidebar_action`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/sidebar_action) manifest key enables extensions to control whether their sidebars should open automatically on install or not ([Firefox bug 1460910](https://bugzil.la/1460910)).
- Changes to the `browser_style` property of various manifest keys:
- In [`page_action`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/page_action) and [`browser_action`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/browser_action) it defaults to `false`.
- In [`sidebar_action`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/sidebar_action) and [`options_ui`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/options_ui) it defaults to `true`.
### Theme changes
- New `tab_background_separator` property of the [`theme`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/theme) manifest key enables extensions to change the color of the tab separator ([Firefox bug 1459455](https://bugzil.la/1459455)).
### Removals
- Support for unpacked sideloaded extensions has been removed ([Firefox bug 1385057](https://bugzil.la/1385057)).
- The warning about `browser_style` displayed when temporarily loading an extension for testing is no longer displayed ([Firefox bug 1404724](https://bugzil.la/1404724)).
## Older versions
{{Firefox_for_developers(61)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/52/index.md | ---
title: Firefox 52 for developers
slug: Mozilla/Firefox/Releases/52
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
Firefox 52 was released on March 7, 2017. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.
## Changes for Web developers
### Developer Tools
- [Completely revamped Responsive Design Mode, including UA selection and network throttling.](https://firefox-source-docs.mozilla.org/devtools-user/responsive_design_mode/index.html)
- [The Animation Inspector now displays timing functions.](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/work_with_animations/index.html)
- [The Page Inspector now includes a CSS grid inspector.](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_grid_layouts/index.html)
- [about:debugging now shows service worker state.](https://firefox-source-docs.mozilla.org/devtools-user/about_colon_debugging/index.html#service-worker-state)
- [The Page Inspector includes an easy way to highlight the selected element.](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_css/index.html#element-rule)
- [The Page Inspector displays whitespace-only text nodes.](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_html/index.html#whitespace-only-text-nodes)
[All devtools bugs fixed between Firefox 51 and Firefox 52](https://bugzilla.mozilla.org/buglist.cgi?resolution=FIXED&classification=Client%20Software&chfieldto=2016-11-14&query_format=advanced&chfield=resolution&chfieldfrom=2016-09-19&chfieldvalue=FIXED&bug_status=RESOLVED&bug_status=VERIFIED&component=Developer%20Tools&component=Developer%20Tools%3A%20about%3Adebugging&component=Developer%20Tools%3A%20Animation%20Inspector&component=Developer%20Tools%3A%20Canvas%20Debugger&component=Developer%20Tools%3A%20Computed%20Styles%20Inspector&component=Developer%20Tools%3A%20Console&component=Developer%20Tools%3A%20CSS%20Rules%20Inspector&component=Developer%20Tools%3A%20Debugger&component=Developer%20Tools%3A%20DOM&component=Developer%20Tools%3A%20Font%20Inspector&component=Developer%20Tools%3A%20Framework&component=Developer%20Tools%3A%20Graphic%20Commandline%20and%20Toolbar&component=Developer%20Tools%3A%20Inspector&component=Developer%20Tools%3A%20JSON%20Viewer&component=Developer%20Tools%3A%20Memory&component=Developer%20Tools%3A%20Netmonitor&component=Developer%20Tools%3A%20Object%20Inspector&component=Developer%20Tools%3A%20Performance%20Tools%20%28Profiler%2FTimeline%29&component=Developer%20Tools%3A%20Responsive%20Design%20Mode&component=Developer%20Tools%3A%20Scratchpad&component=Developer%20Tools%3A%20Shared%20Components&component=Developer%20Tools%3A%20Source%20Editor&component=Developer%20Tools%3A%20Storage%20Inspector&component=Developer%20Tools%3A%20Style%20Editor&component=Developer%20Tools%3A%20User%20Stories&component=Developer%20Tools%3A%20Web%20Audio%20Editor&component=Developer%20Tools%3A%20WebGL%20Shader%20Editor&component=Developer%20Tools%3A%20WebIDE&product=Firefox&list_id=13333174).
### HTML
- The `rel="noopener"` [Link type](/en-US/docs/Web/HTML/Attributes/rel) has been implemented (see [Firefox bug 1222516](https://bugzil.la/1222516)).
### CSS
#### New features
- Added {{cssxref(":focus-within")}} pseudo-class ([Firefox bug 1176997](https://bugzil.la/1176997)).
- Added support for `display:flex/grid` and columnset layout inside {{HTMLElement("button")}} elements ([Firefox bug 984869](https://bugzil.la/984869)).
- Implemented interpolation between numeric color and [currentcolor](/en-US/docs/Web/CSS/color_value#currentcolor_keyword) ([Firefox bug 1299741](https://bugzil.la/1299741)).
- Implemented flexbox layout for `{{cssxref("justify-content")}}: space-evenly` and `{{cssxref("align-content")}}: space-evenly` ([Firefox bug 1235922](https://bugzil.la/1235922)).
- Added support for subpixel antialiasing in CSS {{cssxref("mask")}} / {{cssxref("clip-path")}} ([Firefox bug 1305259](https://bugzil.la/1305259)).
- Implemented CSS Text 3 segment break transformation rules ([Firefox bug 1081858](https://bugzil.la/1081858)).
- Basic shape clipping (as applied via the {{cssxref("clip-path")}} property) can now be applied to SVG content ([Firefox bug 1246741](https://bugzil.la/1246741)).
- Implemented Flexbox layout for {{cssxref("align-self")}}|{{cssxref("justify-self")}}: \[ first | last ]? baseline ([Firefox bug 1221524](https://bugzil.la/1221524)).
- The {{cssxref("touch-action")}} property is now enabled by default on all platforms. (For the full story, see [intent to ship mail #1](https://groups.google.com/forum/#!topic/mozilla.dev.platform/6CGjsm1XpD4) and [intent to ship mail #2](https://groups.google.com/forum/#!topic/mozilla.dev.platform/SYEzvXJKw9M).)
- Flexbox {{cssxref("align-content")}} handling & single-line-sizing should depend on {{cssxref("flex-wrap")}}, not number of lines ([Firefox bug 1090031](https://bugzil.la/1090031)).
- [CSS Animations](/en-US/docs/Web/CSS/CSS_animations) can now be used to animate non-interpolated properties (see [Firefox bug 1064937](https://bugzil.la/1064937)).
- Changed `baseline|last-baseline` to `[ first | last ]? baseline` ([Firefox bug 1313254](https://bugzil.la/1313254)).
- The used value for `left`/`right` is `start` for the block-axis ([Firefox bug 1221565](https://bugzil.la/1221565)).
- Stretching flexible tracks with an indefinite containing block length now respects the min/max size([Firefox bug 1309407](https://bugzil.la/1309407)).
- The initial values of {{cssxref("mask-position")}} and {{cssxref("mask-repeat")}} have been changed to `0% 0%` and `repeat`, respectively ([Firefox bug 1308963](https://bugzil.la/1308963)).
- There have been a number of changes to CSS {{cssxref("<color>")}} values (see [Firefox bug 1295456](https://bugzil.la/1295456)):
- `rgba()` and `hsla()` have now been redefined as aliases of `rgb()` and `hsl()`; both accept the same parameter syntax.
- `rgb(`) and `hsl()` now accept an optional alpha value, e.g. `rgb(255, 0, 0, 0.5)`.
- Color functions now accept space-separated parameters rather than commas, e.g. `rgb(255 0 0 / 0.5)`.
- Alpha values can now be specified as percentages as well as numbers, e.g. `rgb(255 0 0 / 50%)`.
- The hue component in `hsl()` colors can now be specified as an angle, as well as a number, e.g. `hsl(120deg, 60%, 70%)`.
- Firefox's implementation of child-indexed pseudo-classes (such as {{cssxref(":nth-child")}}, {{cssxref(":first-child")}}, and so forth) has been updated to match the CSS selectors level 4 specification: these pseudo-classes now match the appropriate sibling elements rather than the children of their parent element. This allows these pseudo-classes to be used when there is no parent, or the parent is not an {{domxref("Element")}} ([Firefox bug 1300374](https://bugzil.la/1300374).
#### CSS Grids
- [CSS Grids](/en-US/docs/Web/CSS/CSS_grid_layout) are implemented.
#### Changes and removals
- Unprefixed multi-column properties (and added back `-moz` prefixed versions as aliases, for now) ([Firefox bug 1300895](https://bugzil.la/1300895)).
- Stopped wrapping abspos children of flex container in anonymous flex items([Firefox bug 1269045](https://bugzil.la/1269045)).
- Implemented grid container baselines ([Firefox bug 1151204](https://bugzil.la/1151204)).
- Removed `<flex>` min-sizing from the style system ([Firefox bug 1305244](https://bugzil.la/1305244)).
- Remove preference `layout.css.masking.enabled` ([Firefox bug 1308239](https://bugzil.la/1308239)).
- The proprietary `-moz-images-in-menus` and `-moz-images-in-buttons` [media types](/en-US/docs/Web/CSS/@media#media_features) have been removed (see [Firefox bug 1302157](https://bugzil.la/1302157)).
- Removed `-moz-use-text-color` value from color properties; use [`currentcolor`](/en-US/docs/Web/CSS/color_value#currentcolor_keyword) instead ([Firefox bug 1306214](https://bugzil.la/1306214)).
- \[css-grid] 'max-width' set on grid item causes text to overflow ([Firefox bug 1330380](https://bugzil.la/1330380)).
### JavaScript
#### New features
- Support for the async functions has been added. This adds {{jsxref("Statements/async_function", "async function")}}, {{jsxref("Operators/async_function", "async function expression")}}, and the {{jsxref("Operators/await", "await")}} keyword ([Firefox bug 1185106](https://bugzil.la/1185106)).
- Implemented ES2017 [trailing commas](/en-US/docs/Web/JavaScript/Reference/Trailing_commas) in functions ([Firefox bug 1303788](https://bugzil.la/1303788)).
- Implemented {{jsxref("Functions/rest_parameters", "rest parameter destructuring", "#Destructuring_rest_parameters", 1)}} ([Firefox bug 1243717](https://bugzil.la/1243717)).
- The {{jsxref("Operators", "exponentiation operator (**)", "#Exponentiation_(**)", 1)}} is now enabled by default ([Firefox bug 1291212](https://bugzil.la/1291212)).
- You can now use [IANA time zone names](https://www.iana.org/time-zones) in the `timeZone` option of date related APIs like {{jsxref("Intl/DateTimeFormat", "DateTimeFormat")}} or {{jsxref("Date.toLocaleString()")}} ([Firefox bug 837961](https://bugzil.la/837961)).
#### Changes and removals
- [Array destructuring](/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment#array_destructuring) now throws a {{jsxref("SyntaxError")}} when using destructuring rest with trailing comma ([Firefox bug 1041341](https://bugzil.la/1041341)).
- Duplicate `__proto__` properties are now allowed in [object destructuring](/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment) ([Firefox bug 1204024](https://bugzil.la/1204024)).
- {{jsxref("Array.prototype.toLocaleString()")}} has been re-implemented to support the Intl API parameters "`locales`" and "`options`" ([Firefox bug 1130636](https://bugzil.la/1130636)).
- {{jsxref("TypedArray")}} constructors now accept [iterables](/en-US/docs/Web/JavaScript/Reference/Iteration_protocols) to create new typed arrays ([Firefox bug 1232266](https://bugzil.la/1232266)).
- {{jsxref("TypedArray.from()")}}, {{jsxref("TypedArray.of()")}}, {{jsxref("TypedArray.prototype.filter()")}}, {{jsxref("TypedArray.prototype.map()")}}, {{jsxref("TypedArray.prototype.slice()")}}, {{jsxref("TypedArray.prototype.subarray()")}} now require that their `this` values are valid Typed Array constructors ([Firefox bug 1122396](https://bugzil.la/1122396)).
- The non-standard {{jsxref("ArrayBuffer.slice()")}} method (not {{jsxref("ArrayBuffer.prototype.slice()")}}) is deprecated and now presents a warning when used ([Firefox bug 1316913](https://bugzil.la/1316913)).
- [Unicode code point escapes](/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#unicode_code_point_escapes) can now also be used as identifiers (e.g. "`let \u{61} = 123`", see [Firefox bug 1314037](https://bugzil.la/1314037)).
- To conform with ES2015, `\u2e2f` and `ⸯ` now throw when used as identifier, for details see [Firefox bug 917436](https://bugzil.la/917436) and [Firefox bug 1197230](https://bugzil.la/1197230).
### WebAssembly
- Support for [WebAssembly](/en-US/docs/WebAssembly) has been added to Gecko.
### DOM
- The [Selection API](/en-US/docs/Web/API/Selection) has fully shipped, including the new {{domxref("Node/selectstart_event", "selectstart")}} and {{domxref("Document/selectionchange_event", "selectionchange")}} events ([Firefox bug 1309612](https://bugzil.la/1309612)).
- The property {{domxref("Event.composed")}} is now supported; this Boolean value indicates whether or not the event can bubble through the shadow root into the standard DOM ([Firefox bug 1292063](https://bugzil.la/1292063)).
- Only HTML elements, plus the {{SVGElement("svg")}} and {{MathMLElement("math")}} elements, can be put into full-screen mode by calling {{domxref("Element.requestFullscreen()")}} ([Firefox bug 1305928](https://bugzil.la/1305928)).
- [Touch events](/en-US/docs/Web/API/Touch_events) have been re-enabled on Windows desktop platforms — see [Firefox bug 1244402](https://bugzil.la/1244402). (They were disabled in Firefox 24 because they broke a number of major sites; see [Firefox bug 888304](https://bugzil.la/888304).)
- The {{domxref("Element/focusin_event", "focusin")}} and {{domxref("Element/focusout_event", "focusout")}} events are now implemented ([Firefox bug 687787](https://bugzil.la/687787)).
- The {{domxref("isSecureContext")}} property has been implemented (see [Firefox bug 1269052](https://bugzil.la/1269052)).
- The [Web App Manifest](/en-US/docs/Web/Manifest) install event has been renamed {{domxref("Window.appinstalled_event", "appinstalled")}} to avoid confusion with the service worker install event (see {{domxref("ServiceWorkerGlobalScope.install_event", "oninstall")}}). See [Firefox bug 1309099](https://bugzil.la/1309099) for more details about this update.
- The {{domxref("DataTransfer.types")}} property of the [Drag and drop API](/en-US/docs/Web/API/HTML_Drag_and_Drop_API) now returns a frozen array of strings rather than a {{domxref("DOMStringList")}} (see [Firefox bug 1298243](https://bugzil.la/1298243)).
- The `loadstart` and `loadend` events are now fired on {{htmlelement("img")}} elements (see [Firefox bug 1264769](https://bugzil.la/1264769)).
- The {{domxref("Notification.requireInteraction")}} of the [Notifications API](/en-US/docs/Web/API/Notifications_API) has been implemented (see [Firefox bug 862395](https://bugzil.la/862395).)
- The {{domxref("Window.open()")}} method now has a `noopener` [window feature](/en-US/docs/Web/API/Window/open#window_functionality_features) available (see [Firefox bug 1267339](https://bugzil.la/1267339)), which mirrors the functionality of the `rel="noopener"` [Link type](/en-US/docs/Web/HTML/Attributes/rel).
- The {{domxref("CustomElementRegistry.get()")}} method of the [Web Components API](/en-US/docs/Web/API/Web_components) has been implemented (see [Firefox bug 1275838](https://bugzil.la/1275838)).
- [Pointer Event](/en-US/docs/Web/API/Pointer_events) {{domxref("PointerEvent.width","width")}} and {{domxref("PointerEvent.height","height")}} properties now default to a value of 1 (see [Firefox bug 1304315](https://bugzil.la/1304315)).
- The [File and Directory Entries API](/en-US/docs/Web/API/File_and_Directory_Entries_API) has been updated to include changes in the [latest spec](https://wicg.github.io/entries-api/) (see [Firefox bug 1284987](https://bugzil.la/1284987) for the exact details).
- The {{domxref("Event.cancelBubble", "cancelBubble")}} property, which was defined on {{domxref("UIEvent")}}, is now defined on the {{domxref("Event")}} interface instead. See [Firefox bug 1298970](https://bugzil.la/1298970) for more details.
#### Changes and removals
- The Firefox OS APIs that deal with managing phone calls (Contacts, MobileConnection, Icc, etc.) have been removed ([Firefox bug 1311206](https://bugzil.la/1311206)).
- The Firefox OS `Identity` interface has been removed ([Firefox bug 1309030](https://bugzil.la/1309030)).
- The Firefox OS Voicemail API (`MozVoicemail`, `MozVoicemailEvent`, `MozVoicemailStatus`, `Navigator.mozVoicemail`) has been removed ([Firefox bug 1309723](https://bugzil.la/1309723)).
- The Firefox OS Cell Broadcast API (`MozCellBroadcast`, `MozCellBroadcastEvent`, `MozCellBroadcastMessage`, `Navigator.mozCellBroadcast`) has been removed ([Firefox bug 1306772](https://bugzil.la/1306772)).
- The Firefox OS TV broadcast-related APIs have been removed ([Firefox bug 1306778](https://bugzil.la/1306778)).
- The Firefox OS FM Radio API (`FMRadio`, `Navigator.mozFMRadio`) has been removed ([Firefox bug 1306779](https://bugzil.la/1306779)).
### Service Workers and Fetch
- The `Headers.getAll()` method has been removed, and {{domxref("Headers.get()")}} now retrieves all values of the specified header, not just the first one (see [Firefox bug 1278275](https://bugzil.la/1278275)). This is in accordance with the latest Fetch API spec updates.
### Web Audio API
- The {{domxref("ConstantSourceNode")}} interface has been added; it represents an audio source which always outputs a stream of samples which all have the same value. See [Controlling multiple parameters with ConstantSourceNode](/en-US/docs/Web/API/Web_Audio_API/Controlling_multiple_parameters_with_ConstantSourceNode) for an example showing how this can be used to simplify some complex audio flows.
### WebRTC
- When an ICE connection is temporarily disrupted, the {{domxref("RTCPeerConnection.iceConnectionState")}} property now gets set to `"disconnected"`; this indicates a transitory failure that may resolve itself shortly, with the connection returning to the `"connected"` state afterward ([Firefox bug 852665](https://bugzil.la/852665)).
- The {{domxref("MediaDevices.devicechange_event")}} event and its corresponding handler, which were implemented but disabled by default on Mac only in Firefox 51, have been implemented on Windows and Linux and are now enabled by default on all platforms.
- The {{domxref("MediaStream.active")}} property is now supported. This read-only Boolean property indicates whether or not at least one track on the stream is currently playing.
- Prior to Firefox 52, the {{domxref("MediaStreamTrack.stop()")}} method could only stop local tracks (that is, tracks obtained through {{domxref("MediaDevices.getUserMedia", "getUserMedia()")}}). Now a variety of tracks can be stopped, including those on a {{domxref("MediaStream")}} associated with a [WebRTC](/en-US/docs/Glossary/WebRTC) connection, [Web Audio API](/en-US/docs/Web/API/Web_Audio_API) stream, or {{domxref("CanvasCaptureMediaStreamTrack", "CanvasCaptureMediaStream")}}.
- Previously, changing a {{domxref("TextTrack")}}'s {{domxref("TextTrack.mode", "mode")}} repeatedly during a single pass through the Firefox event loop would result in multiple {{domxref("HTMLElement/change_event", "change")}} events being delivered to the {{domxref("TextTrackList")}} specified by the parent media element's {{domxref("HTMLMediaElement.textTracks", "textTracks")}} property. Now these changes are consolidated into one event ([Firefox bug 882674](https://bugzil.la/882674)).
### Audio/Video/Media
- The {{domxref("MediaError")}} objects specified in {{domxref("HTMLMediaElement.error")}} when an error occurs handling an {{HTMLElement("audio")}} or {{HTMLElement("video")}} element now include a {{domxref("MediaError.message", "message")}} property, which provides a specific description of the error which occurred. This string offers details particular to this exact error occurrence, offering insight into why things went wrong ([Firefox bug 1299072](https://bugzil.la/1299072)). This field has been included in Firefox nightly builds since Firefox 51, but is now available in all builds, up to and including release.
### Other APIs
- The method {{domxref("FileSystemFileEntry.createWriter()")}}, which was added (but always returned an error) in Firefox 50 has been removed ([Firefox bug 1315185](https://bugzil.la/1315185).
- The proprietary Firefox OS `Apps installation/management APIs` have been removed from the platform (see [Firefox bug 1261019](https://bugzil.la/1261019)).
- The proprietary Firefox OS `Web Telephony API` has been removed from the platform (see [Firefox bug 1309719](https://bugzil.la/1309719)).
- The proprietary Firefox OS `Web Bluetooth API` has been removed from the platform (see [Firefox bug 1310020](https://bugzil.la/1310020)).
- The [Battery Status API](/en-US/docs/Web/API/Battery_Status_API) is now available only to chrome/privileged code (see [Firefox bug 1313580](https://bugzil.la/1313580)).
- `ImageBitmapRenderingContext.transferImageBitmap()` has been renamed to {{domxref("ImageBitmapRenderingContext.transferFromImageBitmap()")}} (see [Firefox bug 1304767](https://bugzil.la/1304767)).
- The `mozDash` and `mozDashOffset` members have been removed from {{domxref("CanvasRenderingContext2D")}} (see [Firefox bug 931389](https://bugzil.la/931389)).
### HTTP
- The {{HTTPHeader("Referrer-Policy")}} header now supports the directives `same-origin`, `strict-origin`, and `strict-origin-when-cross-origin` ([Firefox bug 1276836](https://bugzil.la/1276836)).
- The [`'strict-dynamic'` source expression](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src#strict-dynamic) is now supported for {{HTTPHeader("Content-Security-Policy")}} directives, such as {{CSP("script-src")}} ([Firefox bug 1299483](https://bugzil.la/1299483)).
- Insecure sites (`http:`) can't [set cookies](/en-US/docs/Web/HTTP/Cookies) with the "secure" directive anymore as per the [Strict Secure Cookies specification](https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-cookie-alone-01) ([Firefox bug 976073](https://bugzil.la/976073)).
- The maximum table size format of the HTTP/2 header compression format [HPACK](https://datatracker.ietf.org/doc/html/rfc7541) has been increased from 4 KB to 64 KB ([Firefox bug 1296280](https://bugzil.la/1296280)).
- The {{HTTPHeader("Large-Allocation")}} header has been added ([Firefox bug 1304140](https://bugzil.la/1304140)).
### SVG
- SVG documents are now represented using the {{domxref("XMLDocument")}} interface instead of SVGDocument. This is a change made in the SVG 2 specification.
### Security
- When login pages (i.e., those containing an [`<input type="password">`](/en-US/docs/Web/HTML/Element/input/password) field) are created so that they would be submitted insecurely, Firefox displays an in-context warning message below the password field to warn users ([Firefox bug 1319119](https://bugzil.la/1319119)). Autofill is also disabled on insecure login forms ([Firefox bug 1217152](https://bugzil.la/1217152)). See [Insecure passwords](/en-US/docs/Web/Security/Insecure_passwords) for more details.
- Support for SHA-1 SSL certificates has been removed; navigating to a secure page that uses a SHA-1 certificate will now result in an `Untrusted Connection` error ([Firefox bug 1330043](https://bugzil.la/1330043)).
## Plugins
All NPAPI plugin support except Flash has been dropped. Flash usage is also set to be phased out in the future.
## Changes for add-on and Mozilla developers
### WebExtensions
New APIs:
- [`sessions` API](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/sessions)
- [`topSites` API](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/topSites)
- [`omnibox` API](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/omnibox)
- [`runtime.onInstalled`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/runtime/onInstalled) and [`runtime.onStartup`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/runtime/onStartup) events
- [asynchronous event listeners in webRequest](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/webRequest#modifying_requests)
- [`bookmarks.onMoved`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/bookmarks/onMoved), [`bookmarks.onCreated`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/bookmarks/onCreated), [`bookmarks.onChanged`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/bookmarks/onChanged) events
- `_execute_browser_action` and `_execute_page_action` in the [commands manifest key](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/commands)
- [`match_about_blank`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/content_scripts#match_about_blank) in the content_scripts manifest key
### Interfaces
- `nsIDroppedLinkHandler.dropLinks` method and `nsIDroppedLinkItem` interface have been added to handle dropping multiple items ([Firefox bug 92737](https://bugzil.la/92737)).
### XUL
- `tabbrowser.loadTabs(uris, params)` method overload has been added ([Firefox bug 92737](https://bugzil.la/92737)).
- `browser.droppedLinkHandler` function signature has been changed ([Firefox bug 92737](https://bugzil.la/92737)).
## Older versions
{{Firefox_for_developers(51)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/30/index.md | ---
title: Firefox 30 for developers
slug: Mozilla/Firefox/Releases/30
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
## Changes for Web developers
### Developer Tools
- A Box Model Highlighter has been implemented ([Firefox bug 663778](https://bugzil.la/663778)).
- Anywhere a DOM node appears in the console output, it is highlighted when you hover over that console output ([Firefox bug 757866](https://bugzil.la/757866)). Similarly all JS functions and objects are highlighted in the console output ([Firefox bug 584733](https://bugzil.la/584733)). More information about the console improvement can be found in this [blog post](https://web.archive.org/web/20150427210606/http://mihai.sucan.ro/mihai/blog/web-console-improvements-episode-30).
- Support for {{domxref("console/count_static", "console.count()")}} has been added ([Firefox bug 922208](https://bugzil.la/922208)).
### CSS
- The property {{cssxref("background-blend-mode")}} has been enabled by default ([Firefox bug 970600](https://bugzil.la/970600)).
- The non-standard `overflow-clip-box` property has been implemented for use in UA stylesheets only ([Firefox bug 966992](https://bugzil.la/966992)).
- The {{cssxref("line-height")}} property now affects single-line text inputs (`<input type=text|password|email|search|tel|url|unknown>` types) although it cannot shrink them below a line height of `1.0` ([Firefox bug 349259](https://bugzil.la/349259)).
- The {{cssxref("line-height")}} property now also affects `type=button`, with no restrictions ([Firefox bug 697451](https://bugzil.la/697451)).
- Change to keyframes' name does not affect current elements ([Firefox bug 978648](https://bugzil.la/978648)).
- positioned internal table elements not abs pos containing block(relative position for table rows) ([Firefox bug 63895](https://bugzil.la/63895)).
### HTML
_No change._
### JavaScript
- New ES2015-compatible [array comprehensions](/en-US/docs/Web/JavaScript/Reference/Deprecated_and_obsolete_features) `[for (item of iterable) item]` and [generator comprehensions](/en-US/docs/Web/JavaScript/Reference/Deprecated_and_obsolete_features) `(for (item of iterable) item)` have been implemented ([Firefox bug 979865](https://bugzil.la/979865)).
- [Typed arrays](/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray#property_access) are now extensible and support new named properties ([Firefox bug 695438](https://bugzil.la/695438)).
- The {{jsxref("Error.prototype.stack")}} property now contains column numbers ([Firefox bug 762556](https://bugzil.la/762556)) and has been improved [when using `Function()` and `eval()` calls](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/stack#stack_of_evaled_code). This can help you to better debug minified or generated JavaScript code.
- The `Promise.cast()` method has been renamed to {{jsxref("Promise.resolve()")}} ([Firefox bug 966348](https://bugzil.la/966348)).
### Interfaces/APIs/DOM
- {{domxref("Navigator.sendBeacon")}} has been implemented, easing telemetry collection ([Firefox bug 936340](https://bugzil.la/936340)).
- Added a `relList` property returning a {{domxref("DOMTokenList")}} to {{domxref("HTMLLinkElement")}}, {{domxref("HTMLAreaElement")}} and {{domxref("HTMLAnchorElement")}} ([Firefox bug 968637](https://bugzil.la/968637)).
- As per the latest specification, the first argument of {{domxref("AudioScheduledSourceNode.start")}} and {{domxref("AudioScheduledSourceNode.stop")}} is now optional and defaults to `0` ([Firefox bug 982541](https://bugzil.la/982541)).
- The method `Navigator.requestWakeLock()` and the non-standard `MozWakeLock` are no longer available from the Web on Desktop ([Firefox bug 963366](https://bugzil.la/963366)).
- The `DOM_VK_ENTER` constant has been removed from {{domxref("KeyboardEvent")}} ([Firefox bug 969247](https://bugzil.la/969247)).
- Web components' `Document.register()` has been adapted to follow the behavior described in the latest version of the specification ([Firefox bug 856140](https://bugzil.la/856140)).
- The non-standard, and deprecated since Firefox 15, `Blob.mozSlice` is no longer supported ([Firefox bug 961804](https://bugzil.la/961804)).
- The non-standard `ArchiveReader` and `ArchiveRequest` are no longer exposed to the Web ([Firefox bug 968883](https://bugzil.la/968883)).
- [WebIDL constructors](https://searchfox.org/mozilla-central/source/dom/webidl/) cannot be called as functions anymore. They need to be preceded by the keyword `new`. ([Firefox bug 916644](https://bugzil.la/916644))
- Added support for a new value (`alpha`) for the second, optional, parameter of the {{domxref("HTMLCanvasElement.getContext()")}} method allowing to define if alpha blending must be stored or not for this context. When not, the per-pixel alpha value in this store is always `1.0`. This allows the back-end to implement a fast-track. ([Firefox bug 982480](https://bugzil.la/982480))
- `WorkerGlobalScope.console` now returns for the regular {{domxref("console")}}; `WorkerConsole` has been removed ([Firefox bug 965860](https://bugzil.la/965860)).
- The {{domxref("WebGL_debug_shaders")}} WebGL extension has been implemented ([Firefox bug 968374](https://bugzil.la/968374)).
### MathML
_No change._
### SVG
- {{SVGElement("feDropShadow")}}, and its interface {{domxref("SVGFEDropShadowElement")}}, from the Filter Effects Module are now supported ([Firefox bug 964200](https://bugzil.la/964200)).
### Audio/Video
- On Linux, Gstreamer 1.0 is now supported (instead of 0.10) ([Firefox bug 806917](https://bugzil.la/806917)).
## Security
_No change._
## Changes for add-on and Mozilla developers
- The interface `nsIDOMWindowUtils` now supports the Boolean attribute `audioMuted` and `audioVolume`, a float in the range `[0.0 , 1.0]`, allowing to control the sound produced by a window (that is any tab or iframe). There is no UI for this, but is available to add-ons. ([Firefox bug 923247](https://bugzil.la/923247))
### Older versions
{{Firefox_for_developers('29')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/25/index.md | ---
title: Firefox 25 for developers
slug: Mozilla/Firefox/Releases/25
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
## Changes for Web developers
### New in Firefox DevTools
- The inspector now features autocompletion for CSS names and values.
- The debugger now lets you "black box" script files, to prevent breakpoints from stopping in library code you're not interested in debugging.
- The Profiler now has the ability to save and import profiling results. "Show Gecko Platform Data" is now an option in the Firefox developer tools options.
- The Network panel has a right-click context menu, with copy and resend URL commands.
- Numerous under-the-hood changes may make some rewriting necessary for addons that modify the DevTools.
### CSS
- The support for the keyword `local` as a value of the {{cssxref("background-attachment")}} CSS property has been added ([Firefox bug 483446](https://bugzil.la/483446)).
- Support of a non-standard Mozilla-only media query to determine the operating system version has been added: [`-moz-os-version`](/en-US/docs/Web/CSS/CSS_media_queries/Using_media_queries#-moz-os-version) ([Firefox bug 810399](https://bugzil.la/810399)). The property is currently only implemented on Windows.
- The `-moz-osx-font-smoothing` CSS property has been added ([Firefox bug 857142](https://bugzil.la/857142)).
- Our experimental support for {{cssxref("filter")}} now supports the `hue-rotate()` functional notation ([Firefox bug 897392](https://bugzil.la/897392)). It is still preffed off by default.
- `page-break-inside`: `avoid` is now working with the height of a block ([Firefox bug 883676](https://bugzil.la/883676)).
### HTML
- The [`srcdoc`](/en-US/docs/Web/HTML/Element/iframe#srcdoc) attribute of {{HTMLElement("iframe")}}, allowing the inline specification of the content of an {{HTMLElement("iframe")}}, is now supported ([Firefox bug 802895](https://bugzil.la/802895)).
- When used with a `"image/jpeg"` type, the method `HTMLCanvasElement.toBlob` now accepts a third attribute defining the quality of the image ([Firefox bug 891884](https://bugzil.la/891884)).
### JavaScript
ECMAScript 2015 implementation continues!
- The method {{jsxref("Array.of()")}} is now implemented on [`Array`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array) ([Firefox bug 866849](https://bugzil.la/866849)).
- Support for the methods {{jsxref("Array.prototype.find()")}} and {{jsxref("Array.prototype.findIndex()")}} has been added ([Firefox bug 885553](https://bugzil.la/885553)).
- The methods {{jsxref("Global_Objects/Number/parseInt", "Number.parseInt()")}} and {{jsxref("Global_Objects/Number/parseFloat", "Number.parseFloat()")}} have been implemented ([Firefox bug 886949](https://bugzil.la/886949))
- The methods {{jsxref("Map.prototype.forEach()")}} and {{jsxref("Set.prototype.forEach()")}} are now implemented ([Firefox bug 866847](https://bugzil.la/866847)).
- New mathematical methods have been implemented on [`Math`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math): `Math.log10()`, `Math.log2()`, `Math.log1p()`, `Math.expm1()`, `Math.cosh()`, `Math.sinh()`, `Math.tanh()`, `Math.acosh()`, `Math.asinh()`, `Math.atanh()`, `Math.trunc()`, `Math.sign()` and `Math.cbrt()` ([Firefox bug 717379](https://bugzil.la/717379)).
- Support for binary and octal integer literals has been added: `0b10101010`, `0B1010`, `0o777`, `0O237` are now valid ([Firefox bug 894026](https://bugzil.la/894026)).
- The machine epsilon constant, that is the smallest representable number that added to 1 will not be 1, is now available as {{jsxref("Global_Objects/Number/EPSILON", "Number.EPSILON")}} ([Firefox bug 885798](https://bugzil.la/885798)).
- [Typed arrays](/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray) have been updated to [no longer search in the prototype chain for indexed properties](/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray#property_access) ([Firefox bug 829896](https://bugzil.la/829896)).
### Interfaces/APIs/DOM
- The [Web Audio API](/en-US/docs/Web/API/Web_Audio_API) is now supported. An incomplete implementation was previously available behind a preference ([Firefox bug 779297](https://bugzil.la/779297)).
- Some IME related keys on Windows are supported by `KeyboardEvent.key` ([Firefox bug 865565](https://bugzil.la/865565)), see [the key name table](/en-US/docs/Web/API/KeyboardEvent#keyname_table_win) for the detail.
- Firefox for Metro now dispatches key events in the same way as the desktop version ([Firefox bug 843236](https://bugzil.la/843236)).
- `keypress` event is no longer dispatched if `preventDefault()` of preceding `keydown` event is called ([Firefox bug 501496](https://bugzil.la/501496)), see [the document of `keydown` event](</en-US/docs/Web/API/Element/keydown_event#preventdefault()_of_keydown_event>) for the detail.
- Renamed the `Future` interface to `Promise` ([Firefox bug 884279](https://bugzil.la/884279)).
- The `srcDoc` property on the {{domxref("HTMLIFrameElement")}} interface, allowing the inline specification of the content of an {{HTMLElement("iframe")}}, is now supported ([Firefox bug 802895](https://bugzil.la/802895)).
- The `createTBody()` method on the {{domxref("HTMLTableElement")}} interface, allowing to get its {{HTMLElement("tbody")}}, is now supported ([Firefox bug 813034](https://bugzil.la/813034)).
- The {{domxref("Range.collapse()")}} method `toStart` parameter is now optional and default to `false`, as defined in the spec ([Firefox bug 891340](https://bugzil.la/891340)).
- Support of the `ParentNode` mixin on {{domxref("Document")}} and {{domxref("DocumentFragment")}} has been added ([Firefox bug 895974](https://bugzil.la/895974)).
- The `previousElementSibling` and `nextElementSibling` have been moved to the `ChildNode` mixin allowing them to be called not only on a {{domxref("Element")}} object but also on a {{domxref("CharacterData")}} or {{domxref("DocumentType")}} object ([Firefox bug 895974](https://bugzil.la/895974)).
- The `navigator.geolocation` property has been updated to match the spec. It never returns `null`. When the preference `geo.enabled` is set to `false`, it now returns `undefined` ([Firefox bug 884921](https://bugzil.la/884921)).
- The `videoPlaybackQuality` attribute on the {{ domxref("HTMLVideoElement") }} interface has been changed to the `getVideoPlaybackQuality` method. ([Firefox bug 889205](https://bugzil.la/889205))
- The non-standard `GlobalObjectConstructor` interface has been removed ([Firefox bug 898136](https://bugzil.la/898136)). This interface was used to add arguments to the constructors of APIs that Firefox [add-ons](/en-US/docs/Mozilla/Add-ons) were exposing on the global object. This capability has been removed; note that at this time there's no replacement for this functionality.
### MathML
_No change._
### SVG
_No change._
### Older versions
{{Firefox_for_developers('24')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/19/index.md | ---
title: Firefox 19 for developers
slug: Mozilla/Firefox/Releases/19
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
Firefox 19 was released on February 19, 2013. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.
## Changes for Web developers
### JavaScript
- [`Map`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) and [`Set`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set) objects have changed from having a `size()` method to a `size` property ([Firefox bug 807001](https://bugzil.la/807001))
- [`Map`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) and [`Set`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set) objects also have a clear() method now. ([Firefox bug 805003](https://bugzil.la/805003))
### CSS
- Support for the viewport-relative {{cssxref("<length>")}} units, `vh`, `vw`, `vmin`, and `vmax`, has landed ([Firefox bug 503720](https://bugzil.la/503720))
- CSS Flexbox has been unprefixed, but remains disabled by default ([Firefox bug 801098](https://bugzil.la/801098)).
- The `-moz-initial` value has been unprefixed ([Firefox bug 806068](https://bugzil.la/806068)). `-moz-initial` will be kept for a while as an alias; however, authors are strongly encouraged to switch over to `initial`.
- The CSS {{cssxref("text-transform")}} property now supports the `full-width` keyword, which allows a more seamless inclusion of Latin characters in text using ideographic fixed-width characters, like Chinese or Japanese ([Firefox bug 774560](https://bugzil.la/774560)).
- The CSS {{cssxref("page-break-inside")}} has been implemented ([Firefox bug 685012](https://bugzil.la/685012)).
- The CSS {{cssxref("calc", "calc()")}} function can now be used on `<color-stop>` (on {{cssxref("<gradient>")}}).
- The CSS {{cssxref("@page")}} at-rule is now supported ([Firefox bug 115199](https://bugzil.la/115199)). Note that the pseudo-classes {{cssxref(":first")}}, {{cssxref(":right")}}, and {{cssxref(":left")}} are not yet implemented.
- The `:-moz-placeholder` pseudo-class is replaced by the `::-moz-placeholder` pseudo-_element_ ([Firefox bug 737786](https://bugzil.la/737786)).
- Declarations qualified with `!important` appearing in {{cssxref("@keyframes")}} are now ignored, per spec ([Firefox bug 784466](https://bugzil.la/784466)).
### DOM/APIs
- The {{domxref("Element.getElementsByTagName")}}, {{domxref("Element.getElementsByTagNameNS")}} and {{domxref("Element.getElementsByClassName")}} methods now return a live {{domxref("HTMLCollection")}} ([Firefox bug 799464](https://bugzil.la/799464)).
- The {{domxref("File")}} `mozLastModifiedDate` property has been implemented. ([Firefox bug 793955](https://bugzil.la/793955))
- The {{domxref("File")}} lastModifiedDate property returns the current date, when the date of the last modification is unknown. ([Firefox bug 793459](https://bugzil.la/793459))
- The {{domxref("CanvasRenderingContext2D")}} `isPointInStroke` method has been implemented ([Firefox bug 803124](https://bugzil.la/803124)).
- The {{domxref("HTMLCanvasElement")}} `toBlob` method has been implemented ([Firefox bug 648610](https://bugzil.la/648610)).
- The `Node.isSupported` and the {{domxref("document.implementation", "document.implementation.hasFeature()")}} methods have been changed to always return `true` ([Firefox bug 801425](https://bugzil.la/801425)).
- When calling `document.createElement(null)`, `null` will now be stringified and works like `document.createElement("null")`.
- The {{domxref("TextDecoder")}} and {{domxref("TextEncoder")}} interfaces have been updated to match the latest spec ([Firefox bug 801487](https://bugzil.la/801487)).
### XForms
Support for XForms has been [**removed**](https://www.philipp-wagner.com/blog/2011/07/the-future-of-mozilla-xforms) in Firefox 19.
## Changes for add-on and Mozilla developers
> **Note:** A key change in Firefox 19 is that `nsresult` is now strongly typed. This will help make it easier to detect bugs that are caused by mishandling of return values, but may cause existing code to break if it's making incorrect assumptions in this regard.
- `getBrowserSelection()` now returns the selected text in a text input field. As a result, `gContextMenu.isTextSelected` will be `true` when the user selects text in a text input field that is not a password field. ([Firefox bug 565717](https://bugzil.la/565717))
- Dict.jsm: `Dict()` now takes a JSON String. `Dict.toJSON()` was added, and it returns a JSON String. ([Firefox bug 727967](https://bugzil.la/727967))
### Interface changes
- `nsIImgLoadingContent`
- : The parameter (aObserver) of `addObserver()` method changes from `imgIDecoderObserver` to `imgINotificationObserver`. The `notify()` method of `imgINotificationObserver` is not scriptable, so you need to use `createScriptedObserver()` from `imgITools`.
- `nsIChannel`
- : The property `contentLength` changed from `long` to `int64_t`.
## See also
- [Firefox 19 Beta Release Notes](https://website-archive.mozilla.org/www.mozilla.org/firefox_releasenotes/en-us/firefox/19.0beta/releasenotes/)
- [Add-on Compatibility for Firefox 19](https://blog.mozilla.org/addons/2013/02/07/compatibility-for-firefox-19/)
### Older versions
{{Firefox_for_developers('18')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/95/index.md | ---
title: Firefox 95 for developers
slug: Mozilla/Firefox/Releases/95
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 95 that will affect developers.
Firefox 95 was released on December 7, 2021.
## Changes for web developers
### HTML
- The [`inputmode`](/en-US/docs/Web/HTML/Global_attributes/inputmode) global attribute is now supported on all platforms, instead of just Android.
This provides a hint to browsers about the type of virtual keyboard that would be best suited to editing a particular element ([Firefox bug 1205133](https://bugzil.la/1205133)).
### CSS
- The CSS [`cursor`](/en-US/docs/Web/CSS/cursor) property is now supported on Firefox for Android,
making it easier for Android users with a mouse to determine which elements are clickable ([Firefox bug 1672609](https://bugzil.la/1672609)).
### JavaScript
No notable changes
### APIs
- The {{domxref("Crypto.randomUUID()")}} function is now supported. This returns a cryptographically strong 36 character fixed-length UUID ([Firefox bug 1723674](https://bugzil.la/1723674)).
#### Media, WebRTC, and Web Audio
- {{domxref("SpeechSynthesisEvent.elapsedTime")}} now returns the elapsed time in seconds rather than milliseconds, matching an update to the specification (see [Firefox bug 1732498](https://bugzil.la/1732498)).
### WebDriver conformance (Marionette)
- The `port` used by Marionette is now written to the `MarionetteActivePort` file in the profile directory. This can be used to easily retrieve the `port`, which before was only possible by parsing the `prefs.js` file of the profile. ([Firefox bug 1735162](https://bugzil.la/1735162)).
- `WebDriver:NewSession` now waits for the initial tab to have completed loading to prevent unexpected unloads of the window proxy. ([Firefox bug 1736323](https://bugzil.la/1736323)).
## Changes for add-on developers
- Added `overrideContentColorScheme` in {{WebExtAPIRef("browserSettings")}} to provide the ability to control the preference `layout.css.prefers-color-scheme.content-override` and set pages' preferred color scheme (light or dark) independently of the browser theme ([Firefox bug 1733461](https://bugzil.la/1733461)).
- Added `globalPrivacyControl` in {{WebExtAPIRef("privacy.network")}} to provide visibility into whether the user has enabled Global Privacy Control inside the browser. ([Firefox bug 1670058](https://bugzil.la/1670058)).
- Added the `"webRequestFilterResponse.serviceWorkerScript"` [API permission](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/permissions#api_permissions). This permission provides access to {{WebExtAPIRef("webRequest.filterResponseData")}} for requests originated for service worker scripts. This permission can be provided as an optional permission. See {{WebExtAPIRef("webRequest.filterResponseData")}} for more information on using these permissions ([Firefox bug 1636629](https://bugzil.la/1636629)).
## Older versions
{{Firefox_for_developers(94)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/22/index.md | ---
title: Firefox 22 for developers
slug: Mozilla/Firefox/Releases/22
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
## Changes for Web developers
### HTML
- The HTML5 {{HTMLElement("data")}} element has been implemented ([Firefox bug 839371](https://bugzil.la/839371)).
- The HTML5 {{HTMLElement("time")}} element has been implemented ([Firefox bug 629801](https://bugzil.la/629801)).
- The `range` state of the {{HTMLElement("input")}} element (`<input type="range">`) has been implemented, behind the preference `dom.experimental_forms_range`, only enabled by default on Nightly and Aurora channel ([Firefox bug 841948](https://bugzil.la/841948)).
- The support for the {{HTMLElement("template")}} element, part of the Web component specification has been implemented ([Firefox bug 818976](https://bugzil.la/818976)).
### JavaScript
- [Asm.js](http://asmjs.org/spec/latest/) optimizations are enabled, making it possible to compile C/C++ applications to a subset of JavaScript for better performance.
- ES2015 [Arrow Function](/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions) syntax has been implemented ([Firefox bug 846406](https://bugzil.la/846406)).
- The new [Object.is](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is) function has been added ([Firefox bug 839979](https://bugzil.la/839979)).
- [`arguments`](/en-US/docs/Web/JavaScript/Reference/Functions/arguments) in generator expressions is now inherited from enclosing lexical scope ([Firefox bug 848051](https://bugzil.la/848051)).
- The ES2015 Proxy {{jsxref("Global_Objects/Proxy/Proxy/preventExtensions", "preventExtensions")}} trap have been implemented ([Firefox bug 789897](https://bugzil.la/789897)).
### DOM
- Support for the `multipart` property on `XMLHttpRequest` and `multipart/x-mixed-replace` responses in `XMLHttpRequest` has been removed. This was a Gecko-only feature that was never standardized. [Server-Sent Events](/en-US/docs/Web/API/Server-sent_events), [Web Sockets](/en-US/docs/Web/API/WebSockets_API) or inspecting `responseText` from progress events can be used instead.
- Support for [Web Notifications](/en-US/docs/Web/API/Notifications_API/Using_the_Notifications_API) has been landed ([Firefox bug 782211](https://bugzil.la/782211)).
- The {{domxref("FormData")}} `append` method now accepts a third optional `filename` parameter ([Firefox bug 690659](https://bugzil.la/690659)).
- `Node.isSupported` has been removed ([Firefox bug 801562](https://bugzil.la/801562)).
- `Node.setUserData` and `Node.getUserData` has been removed for web content and are deprecated for chrome content ([Firefox bug 842372](https://bugzil.la/842372)).
- The {{domxref("Element.attributes")}} property has been moved there from {{domxref("Node")}} as required by the spec ([Firefox bug 844134](https://bugzil.la/844134)).
- The Mac OS X backend for **Ambient Light Events** has been implemented.
- Elements in the HTML namespace with local names `<bgsound>`, {{HTMLElement("multicol")}}, and {{HTMLElement("image")}} no longer implement the {{domxref("HTMLSpanElement")}} interface. `<bgsound>` implements {{domxref("HTMLUnknownElement")}} and {{HTMLElement("image")}} implements {{domxref("HTMLElement")}}.
- The {{ domxref("NodeIterator.detach") }} method has been changed to do nothing ([Firefox bug 823549](https://bugzil.la/823549)).
- The {{domxref("BlobEvent")}} interface has been implemented ([Firefox bug 834165](https://bugzil.la/834165)).
- The properties `HTMLMediaElement.crossorigin` and `HTMLInputElement.inputmode` has been removed to match the spec in {{domxref("HTMLMediaElement.crossOrigin")}} and `HTMLInputElement.inputMode`, respectively ([Firefox bug 847370](https://bugzil.la/847370) and [Firefox bug 850346](https://bugzil.la/850346)).
- WebRTC: the Media Stream API and Peer Connection API are now supported by default.
- Web Components: the {{domxref("Document.register")}} method has been implemented ([Firefox bug 783129](https://bugzil.la/783129)).
- The `ProgressEvent.initProgressEvent()` constructor method has been removed. Use the standard constructor, {{domxref("ProgressEvent.ProgressEvent", "ProgressEvent()")}} to construct and initialize {{domxref("ProgressEvent")}} ([Firefox bug 843489](https://bugzil.la/843489)).
- Manipulated data associated with a {{domxref("Element/cut_event", "cut")}}, {{domxref("Element/copy_event", "copy")}}, or {{domxref("Element/paste_event", "paste")}} event can now be accessed via the {{domxref("ClipboardEvent.clipboardData")}} property ([Firefox bug 407983](https://bugzil.la/407983)).
- The {{domxref("HTMLTimeElement")}} interface has been implemented ([Firefox bug 629801](https://bugzil.la/629801)).
- When a {{domxref("Worker")}} constructor is passed an invalid URL, it now throws {{domxref("DOMException")}} of type `SECURITY_ERR` ([Firefox bug 587251](https://bugzil.la/587251)).
### CSS
- Support for [CSS Flexbox layout](/en-US/docs/Web/CSS/CSS_flexible_box_layout/Basic_concepts_of_flexbox) has been enabled by default ([Firefox bug 841876](https://bugzil.la/841876)).
- Following a spec change, the initial value for {{cssxref("min-width")}} and {{cssxref("min-height")}} has been changed back to `0`, even on flex items ([Firefox bug 848539](https://bugzil.la/848539)).
- Support for CSS Conditionals ({{cssxref("@supports")}} and {{domxref("CSS.supports_static", "CSS.supports()")}}) has been enabled by default ([Firefox bug 855455](https://bugzil.la/855455)).
- Support for {{cssxref("background-clip")}} and {{cssxref("background-origin")}} properties in the {{cssxref("background")}} shorthand has been implemented ([Firefox bug 570896](https://bugzil.la/570896)).
## Changes for add-on and Mozilla developers
- The `properties` parameter has been removed from the `nsITreeView.getCellProperties()`, `nsITreeView.getColumnProperties()` and `nsITreeView.getRowProperties()` methods of `nsITreeView`. These methods should now return a string of space-separated property names ([Firefox bug 407956](https://bugzil.la/407956)).
- The `inIDOMUtils.getCSSPropertyNames()` method has been implemented and will return all supported [CSS property](/en-US/docs/Web/CSS/Reference) names.
- See [here](https://blog.mozilla.org/addons/2013/06/03/compatibility-for-firefox-22/) for more changes.
### Firefox Developer Tools
- [Font inspector](https://hacks.mozilla.org/2013/04/developer-tools-update-firefox-22/) shows which fonts on your computer are applied to the page.
- Visual paint feedback mode shows when and where a page is repainted.
- The dev tools may now be docked to the right side, not just the bottom of the browser.
- Some panes within the dev tools have switched from [XUL to HTML](https://bugzil.la/875727). For example, the CSS rule viewer is now chrome://browser/content/devtools/cssruleview\.xhtml, not `cssruleview.xul`. Instead of adding an overlay directly to extend features of these panes, you may add an overlay and script to the outer xul document, to add load listeners and change these HTML documents.
- The stack trace is now shown as a breadcrumb near the top, and the script listing is now at the left panel of the debugger.
## See also
- [Firefox 22 Beta Release Notes](https://website-archive.mozilla.org/www.mozilla.org/firefox_releasenotes/en-us/firefox/22.0beta/releasenotes/)
- [Add-on Compatibility for Firefox 22](https://blog.mozilla.org/addons/2013/06/03/compatibility-for-firefox-22/)
### Versions
{{Firefox_for_developers('21')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/1.5/index.md | ---
title: Firefox 1.5 for developers
slug: Mozilla/Firefox/Releases/1.5
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
Based on the [Gecko](/en-US/docs/Glossary/Gecko) 1.8 engine, Firefox 1.5 improved its already best in class standards support, and provided new capabilities to enable the next generation of web applications. Firefox 1.5 features improved support for CSS2 and CSS3, APIs for scriptable and programmable 2D graphics through [SVG](/en-US/docs/Web/SVG) 1.1 and [`<canvas>`](/en-US/docs/Web/API/Canvas_API), [XForms](/en-US/docs/Glossary/XForms) and XML events, as well as many DHTML, JavaScript, and DOM enhancements.
## Developer Tools
Several tools and browser extensions are available to help developers support Firefox 1.5.
- [DOM Inspector](/en-US/docs/DOM_Inspector), a tool that allows developers to inspect and modify documents without having to edit the document directly. DOM Inspector is available as part of the Custom install option in Firefox 1.5 under Developer Tools.
- JavaScript console, a tool to write and test JavaScript code as well as view JavaScript and CSS errors on a page.
- View page source, with syntax highlighting and find features.
- [Browser extensions](https://addons.mozilla.org/en-US/firefox/search/?q=Developer%20Tools) including the [FireBug](https://web.archive.org/web/20061205073236/http://www.joehewitt.com/software/firebug/), [Web Developer toolbar](</en-US/docs/Web_Developer_Extension_(external)>), [Live HTTP Headers](</en-US/docs/Live_HTTP_Headers_(external)>), [HTML Validator](</en-US/docs/HTML_Validator_(external)>) and many more.
> **Note:** Some extensions do not currently support Firefox 1.5, and will be automatically disabled.
## Overview
Some of the new features in Firefox 1.5:
### Website and application developers
- SVG is supported in XHTML
- : SVG can be used in XHTML pages. JavaScript and CSS can be used to manipulate the picture in the same way you would script regular XHTML. See [SVG in Firefox](/en-US/docs/Web/SVG/SVG_1.1_Support_in_Firefox) to learn about the status and known problems of SVG implementation in Firefox.
- [Drawing Graphics with Canvas](/en-US/docs/Web/API/Canvas_API/Tutorial)
- : Learn about the new `<canvas>` tag and how to draw graphs and other objects in Firefox.
- [CSS3 Columns](/en-US/docs/Web/CSS/CSS_multicol_layout/Using_multicol_layouts)
- : Learn about the new support for automatic multi-column text layout as proposed for [CSS3](/en-US/docs/Web/CSS).
- [Using Firefox 1.5 caching](/en-US/docs/Mozilla/Firefox/Releases/1.5/Using_Firefox_1.5_caching)
- : Learn about `bfcache` and how it speeds up back and forward navigation.
### XUL and Extension Developers
- [Building an Extension](/en-US/docs/Mozilla/Add-ons)
- : This tutorial will take you through the steps required to build a very basic extension for Firefox. Also see [another tutorial on MozillaZine knowledge base](https://kb.mozillazine.org/Getting_started_with_extension_development), which demonstrates the new features of the Extension Manager in 1.5 that make creating a new extension even easier.
- [XPCNativeWrapper](/en-US/docs/XPCNativeWrapper)
- : `XPCNativeWrapper` is a way to wrap up an object so that it's [safe to access from privileged code](/en-US/docs/Safely_accessing_content_DOM_from_chrome). It can be used in all Firefox versions, though the behavior changed somewhat starting with Firefox 1.5 (Gecko 1.8).
- [Preferences System](/en-US/docs/Preferences_System)
- : Learn about the new widgets that allow you to create Options windows easier using less JavaScript code.
- [International characters in XUL JavaScript](/en-US/docs/International_characters_in_XUL_JavaScript)
- : XUL JavaScript files can now contain non-{{Glossary("ASCII")}} characters.
- [Tree API changes](/en-US/docs/Tree_Widget_Changes)
- : The interfaces for accessing XUL `<tree>` elements have changed.
- [XUL Changes for Firefox 1.5](/en-US/docs/XUL_Changes_for_Firefox_1.5)
- : Summary of XUL changes. See also [Adapting XUL Applications for Firefox 1.5](/en-US/docs/Mozilla/Firefox/Releases/1.5/Adapting_XUL_Applications_for_Firefox_1.5).
#### Networking-related changes
- Certificate prompts can now be overridden on a per-channel basis. This works by setting an interface requester as an `nsIChannel`'s notificationCallbacks and giving out an interface for `nsIBadCertListener`.
- nsIWebBrowserPersist's listeners can now implement `nsIInterfaceRequestor::GetInterface` and will get an opportunity to provide all interfaces that channels might ask for, including `nsIProgressEventSink` (not too useful, redundant with `nsIWebProgressListener`). Useful interfaces here include `nsIChannelEventSink` and `nsIBadCertListener`.
- Extensions or other necko consumers, including XMLHttpRequest, can set a Cookie header explicitly, and necko will not replace it. Stored cookies will be merged with the explicitly set header, in a way that the explicit header will override the stored cookies.
## New End user Features
### User Experience
- **Faster browser navigation** with improvements to back and forward button performance.
- **Drag and drop reordering for browser tabs.**
- **Answers.com is added to the search engine list** for dictionary lookup.
- **Improvements to product usability** including descriptive error pages, redesigned options menu, RSS discovery, and "Safe Mode" experience.
- **Better accessibility support** including DHTML accessibility.
- **Report a broken website wizard** to report websites that are not working in Firefox.
- **Better support for Mac OS X** (10.2 and greater) including profile migration from Safari and Mac Internet Explorer.
### Security and Privacy
- **Automated update** to streamline product upgrades. Notification of an update is more prominent, and updates to Firefox may now be half a megabyte or smaller. Updating extensions has also improved.
- **Improvements to popup blocking.**
- **Clear Private Data** feature provides an easy way to quickly remove personal data through a menu item or keyboard shortcut.
### Support for open Web standards
Firefox support for Web standards continues to lead the industry with consistent cross-platform implementations for:
- Hypertext Markup Language ([HTML](/en-US/docs/Web/HTML)) and Extensible Hypertext Markup Language ([XHTML](/en-US/docs/Glossary/XHTML)): [HTML 4.01](https://www.w3.org/TR/html401/) and [XHTML 1.0/1.1](https://www.w3.org/TR/xhtml1/)
- Cascading Style Sheets ([CSS](/en-US/docs/Web/CSS)): [CSS Level 1](https://www.w3.org/TR/REC-CSS1/), [CSS Level 2](https://www.w3.org/TR/CSS22/) and parts of [CSS Level 3](https://www.w3.org/Style/CSS/current-work.html)
- Document Object Model ([DOM](/en-US/docs/Web/API/Document_Object_Model)): [DOM Level 1](https://www.w3.org/TR/2000/WD-DOM-Level-1-20000929/), [DOM Level 2](https://www.w3.org/DOM/DOMTR#dom2) and parts of [DOM Level 3](https://www.w3.org/DOM/DOMTR#dom3)
- Mathematical Markup Language: [MathML Version 2.0](https://www.w3.org/Math/)
- Extensible Markup Language ([XML](/en-US/docs/Web/XML)): [XML 1.0](https://www.w3.org/TR/REC-xml/), [Namespaces in XML](https://www.w3.org/TR/REC-xml-names/), [Associating Style Sheets with XML Documents 1.0](https://www.w3.org/TR/xml-stylesheet/), [Fragment Identifier for XML](https://lists.w3.org/Archives/Public/www-xml-linking-comments/2001AprJun/att-0074/01-NOTE-FIXptr-20010425.htm)
- XSL Transformations ([XSLT](/en-US/docs/Web/XSLT)): [XSLT 1.0](https://www.w3.org/TR/xslt/)
- XML Path Language ([XPath](/en-US/docs/Web/XPath)): [XPath 1.0](https://www.w3.org/TR/xpath/)
- Resource Description Framework ([RDF](/en-US/docs/Glossary/RDF)): [RDF](https://www.w3.org/RDF/)
- Simple Object Access Protocol (SOAP): [SOAP 1.1](https://www.w3.org/TR/2000/NOTE-SOAP-20000508/)
- [JavaScript](/en-US/docs/Web/JavaScript) 1.6, based on [ECMA-262, revision 3](https://www.ecma-international.org/publications-and-standards/standards/ecma-262/)
Firefox 1.5 supports the following data transport protocols (HTTP, FTP, SSL, TLS, and others), multilingual character data (Unicode), graphics (GIF, JPEG, PNG, SVG, and others) and the latest version of the world's most popular scripting language, [JavaScript 1.6](/en-US/docs/New_in_JavaScript_1.6).
## Changes since Firefox 1.0
Many changes have been introduced into Firefox since it was first released on November 9, 2004. Firefox has progressed with many new features and bug fixes. A detailed list of changes is available from [squarefree.com](https://www.squarefree.com/burningedge/releases/1.5-comprehensive.html).
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases/1.5 | data/mdn-content/files/en-us/mozilla/firefox/releases/1.5/adapting_xul_applications_for_firefox_1.5/index.md | ---
title: Adapting XUL Applications for Firefox 1.5
slug: Mozilla/Firefox/Releases/1.5/Adapting_XUL_Applications_for_Firefox_1.5
page-type: guide
---
{{FirefoxSidebar}}
This page contains a list of changes in [Firefox 1.5](/en-US/docs/Mozilla/Firefox/Releases/1.5), affecting XUL developers.
### Specific Changes
- [Tree Widget Changes](/en-US/docs/Tree_Widget_Changes)
- [International characters in XUL JavaScript](/en-US/docs/International_characters_in_XUL_JavaScript) (only affects extensions with JavaScript files containing non-ASCII characters)
- [XMLHttpRequest changes](/en-US/docs/XMLHttpRequest_changes_for_Gecko1.8)
- [XUL Changes for Firefox 1.5](/en-US/docs/XUL_Changes_for_Firefox_1.5)
- [XPCNativeWrappers](/en-US/docs/XPCNativeWrapper) are on by default, and the behavior changed somewhat compared to 1.0.x
- A simpler method of [Chrome Registration](/en-US/docs/Chrome_Registration) deprecates contents.rdf.
- For overlaid context menus: the function `gContextMenu.linkURL()` has been renamed to `gContextMenu.getLinkURL()`, and `linkURL` is now a property. To use it in a backwards-compatible way:
`url = 'getLinkURL' in gContextMenu ? gContextMenu.getLinkURL() : gContextMenu.linkURL();`
### Other Information
- [How to check application's version using nsIXULAppInfo](/en-US/docs/Using_nsIXULAppInfo)
- [MozillaZine](https://kb.mozillazine.org/Dev_:_Extensions_:_Cross-Version_Compatibility_Techniques)
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases/1.5 | data/mdn-content/files/en-us/mozilla/firefox/releases/1.5/using_firefox_1.5_caching/index.md | ---
title: Using Firefox 1.5 caching
slug: Mozilla/Firefox/Releases/1.5/Using_Firefox_1.5_caching
page-type: guide
---
{{FirefoxSidebar}}
[Firefox 1.5](/en-US/docs/Mozilla/Firefox/Releases/1.5) uses in-memory caching for entire Web pages, including their JavaScript states, for a single browser session. Going backward and forward between visited pages requires no page loading and the JavaScript states are preserved. This feature, referred to by some as **bfcache** (for "Back-Forward Cache"), makes page navigation very fast. This caching state is preserved until the user closes the browser.
There are instances in which Firefox doesn't cache pages. Below are some common programmatic reasons that a page is not cached:
- the page uses an `unload` or `beforeunload` handler;
- the page sets "cache-control: no-store".
- the site is HTTPS and page sets at least one of:
- "Cache-Control: no-cache"
- "Pragma: no-cache"
- with "Expires: 0" or "Expires" with a date value in the past relative to the value of the "Date" header (unless "Cache-Control: max-age=" is also specified);
- the page is not completely loaded when the user navigates away from it or has pending network requests for other reasons (e.g. `XMLHttpRequest`));
- the page has running IndexedDB transactions;
- the top-level page contains frames (e.g. {{HTMLElement("iframe")}}) that are not cacheable for any of the reasons listed here;
- the page is in a frame and the user loads a new page within that frame (in this case, when the user navigates away from the page, the content that was last loaded into the frames is what is cached).
This new caching feature changes page loading behavior, and Web authors may want to:
- know that a page has been navigated to (when it is being loaded from a user's cache)
- define page behavior when a user leaves the page (while still enabling the page to be cached)
Two new browser events enable Web authors to do both.
## New browser events
If you use these new events, your pages will continue to display properly in other browsers (we've tested earlier versions of Firefox, Internet Explorer, Opera, and Safari), and will use this new caching functionality when loaded in Firefox 1.5.
Note: as of 10-2009 development versions of Safari added support for these new events (see [the WebKit bug](https://webkit.org/b/28758)).
Standard behavior for Web pages is:
1. User navigates to a page.
2. As the page loads, inline scripts run.
3. Once the page is loaded, the `onload` handler fires.
Some pages include a fourth step. If a page uses an `unload` or `beforeunload` handler, it fires when the user navigates away from the page. If an `unload` handler is present, the page will not be cached.
When a user navigates to a cached page, inline scripts and the `onload` handler do not run (steps 2 and 3), since in most cases, the effects of these scripts have been preserved.
If the page contains scripts or other behaviors that fire during loading that you want to continue to execute every time the user navigates to the page, or if you want to know when a user has navigated to a cached page, use the new `pageshow` event.
If you have behaviors that fire when a user navigates away from the page, but you want to take advantage of this new caching feature, and therefore don't want to use the unload handler, use the new `pagehide` event.
### pageshow event
This event works the same as the `load` event, except that it fires every time the page is loaded (whereas the `load` event doesn't fire in Firefox 1.5 when the page is loaded from cache). The first time the page loads, the `pageshow` event fires just after the firing of the `load` event. The `pageshow` event uses a boolean property called `persisted` that is set to `false` on the initial load. It is set to `true` if it is not the initial load (in other words, it is set to true when the page is cached).
Set any JavaScript that you want to run every time a page loads to run when the `pageshow` event fires.
If you call JavaScript functions as part of the `pageshow` event, you can ensure these functions are called when the page is loaded in browsers other than Firefox 1.5 by calling the `pageshow` event as part of the `load` event, as shown in the sample later in this article.
### pagehide event
If you want to define behavior that occurs when the user navigates away from the page, but you don't want to use the `unload` event (which would cause the page to not be cached), you can use the new `pagehide` event. Like `pageshow`, the `pagehide` event uses a boolean property called `persisted`. This property is set to `false` if the page is not cached by the browser and set to `true` if the page is cached by the browser. When this property is set to `false`, the `unload` handler, if present, fires immediately after the `pagehide` event.
Firefox 1.5 tries to simulate load events in the same order they would occur when the page is initially loaded. Frames are treated the same way as the top-level document. If the page contains frames, then when the cached page is loaded:
- `pageshow` events from each frame fire before the `pageshow` event in the main document fires.
- When the user navigates away from the cached page, the `pagehide` event from each frame fires before the `pagehide` event in the main document.
- For navigation that occurs inside a single frame, events fire only in the affected frame.
## Sample code
The sample below illustrates a page that uses both the `load` and `pageshow` events. This sample page behaves as follows:
- In browsers other than Firefox 1.5, the following occurs each time the page loads: the `load` event triggers the `onLoad` function, which calls the `onPageShow` function (as well as an additional function).
- In Firefox 1.5, the first time the page is loaded, the `load` event operates the same way as in other browsers. In addition, the `pageshow` event fires, and as `persisted` is set to `false`, no additional action occurs.
- In Firefox 1.5, when the page is loaded from cache, only the `pageshow` event fires. As `persisted` is set to `true`, only the JavaScript actions in the `onPageShow` function are triggered.
In this example:
- The page calculates and displays the current date and time each time the page is loaded. This calculation includes the seconds and milliseconds so you can easily test the functionality.
- The cursor is placed in the Name field of the form the first time the page is loaded. In Firefox 1.5, when the user navigates back to the page, the cursor remains in the field it was when the user navigated away from the page. In other browsers, the cursor moves back to the Name field.
```html
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Order query Firefox 1.5 Example</title>
<style type="text/css">
body,
p {
font-family: Verdana, sans-serif;
font-size: 12px;
}
</style>
<script>
function onLoad() {
loadOnlyFirst();
onPageShow();
}
function onPageShow() {
//calculate current time
var currentTime = new Date();
var year = currentTime.getFullYear();
var month = currentTime.getMonth() + 1;
var day = currentTime.getDate();
var hour = currentTime.getHours();
var min = currentTime.getMinutes();
var sec = currentTime.getSeconds();
var mil = currentTime.getMilliseconds();
var displayTime =
month +
"/" +
day +
"/" +
year +
" " +
hour +
":" +
min +
":" +
sec +
":" +
mil;
document.getElementById("timefield").value = displayTime;
}
function loadOnlyFirst() {
document.zipForm.name.focus();
}
</script>
</head>
<body onload="onLoad();" onpageshow="if (event.persisted) onPageShow();">
<h2>Order query</h2>
<form
name="zipForm"
action="http://www.example.com/formresult.html"
method="get">
<label for="timefield">Date and time:</label>
<input type="text" id="timefield" /><br />
<label for="name">Name:</label>
<input type="text" id="name" /><br />
<label for="address">Email address:</label>
<input type="text" id="address" /><br />
<label for="order">Order number:</label>
<input type="text" id="order" /><br />
<input type="submit" name="submit" value="Submit Query" />
</form>
</body>
</html>
```
In contrast, if the above page did not listen for the `pageshow` event and handled all calculations as part of the `load` event (and instead was coded as shown in the sample code fragment below), both the cursor position and date/time would be cached in Firefox 1.5 when the user navigated away from the page. When the user returned to the page, the cached date/time would display.
```html
<script>
function onLoad() {
loadOnlyFirst();
//calculate current time
var currentTime= new Date();
var year = currentTime.getFullYear();
var month = currentTime.getMonth()+1;
var day = currentTime.getDate();
var hour=currentTime.getHours();
var min=currentTime.getMinutes();
var sec=currentTime.getSeconds();
var mil=currentTime.getMilliseconds();
var displayTime = (month + "/" + day + "/" + year + " " +
hour + ":" + min + ":" + sec + ":" + mil);
document.getElementById("timefield").value=displayTime;
}
function loadOnlyFirst() {
document.zipForm.name.focus();
}
</script>
</head>
<body onload="onLoad();">
```
## Developing Firefox extensions
Firefox 1.5 [extensions](/en-US/docs/Mozilla/Add-ons) need to allow for this caching functionality. If you are developing a Firefox extension that you want to be compatible with both 1.5 and earlier versions, make sure that it listens for the `load` event for triggers that can be cached and listens for the `pageshow` event for triggers that shouldn't be cached.
For instance, the Google Toolbar for Firefox should listen for the `load` event for the autolink function and to the `pageshow` event for the PageRank function in order to be compatible with both 1.5 and earlier versions.
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases/1.5 | data/mdn-content/files/en-us/mozilla/firefox/releases/1.5/what_s_new_in_1.5_alpha/index.md | ---
title: What's New in Deer Park Alpha
slug: Mozilla/Firefox/Releases/1.5/What_s_new_in_1.5_alpha
page-type: guide
---
{{FirefoxSidebar}}
This page is based largely on [https://www.squarefree.com/burningedg...eases/](https://www.squarefree.com/burningedge/releases/) (thanks Jesse).
### New Web Developer Features
#### HTML
- Elements with `tabindex="-1"` should be focusable
- : Elements with a negative tabIndex attribute can now have focus, even though they are not in the tab order.
- Object should submit
- : In accordance with the HTML4 specification, `<object>` elements can now be submitted as part of a form.
#### CSS
- CSS2 quotes nesting
- : Starting with this release, the [`quotes` CSS2 property](https://www.w3.org/TR/CSS21/generate.html#quotes-specify) is fully supported, with the correct quote (depending on the nesting level) used for open-quote and close-quote.
- CSS3 `:only-child`
- : This CSS3 selector allows [selecting an element](https://www.w3.org/TR/2001/CR-css3-selectors-20011113/#only-child-pseudo) that has no other elements as siblings in the DOM.
- CSS3 columns
- : An experimental implementation of the proposed [CSS3 multicolumn layout](https://www.w3.org/TR/2001/WD-css3-multicol-20010118/) draft. This allows easily doing newspaper-like multicolumn presentation.
- CSS3 `overflow-x` and `overflow-y` properties
- : These properties can be used to control the overflow behavior in the horizontal and vertical directions somewhat independently. For example, overflow in the horizontal direction could be hidden while overflow in the vertical direction can be scrolled to.
- CSS3 cursors
- : More [mouse cursor names](https://www.w3.org/TR/css-ui-3/#cursor) are now supported.
- URI values on CSS `cursor` properties
- : On Windows, OS/2 and Linux (Gtk+ 2.x) one can now use an arbitrary image as the mouse cursor while a given DOM node is being hovered.
Any image format supported by Gecko can be used for the image.
(SVG, animated GIF, and ANI cursors are not supported.)
See {{CSSxRef("cursor")}} for a description of the feature.
- `-moz-outline-radius`
- : CSS outlines can now have rounded corners.
- CSS `outline` property
- : [CSS outlines](https://www.w3.org/TR/css-ui-3/#outline1) can now be used. These differ from borders in that they don't affect the page layout.
- Counters in CSS-generated content
- : [CSS2 counters](https://www.w3.org/TR/CSS21/generate.html#counters) are now completely supported (the implementation doesn't match the current CSS2.1 draft, but matches the upcoming one). This allows automatic numbering of sections, headings, and so forth via stylesheets.
#### JavaScript and DOM
- Array extras
- : New methods have been added to the Array object to facilitate common tasks. See [JavaScript 1.5 Array Object](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array).
- `document.open("text/plain")`
- : Text written in new documents created with document.open("text/plain") is now treated as text rather than HTML, so line breaks will remain intact and tags will not be parsed.
- XML Events
- : "XML Events" is a W3C specification to provide XML languages with the ability to integrate declarative event listeners and event handlers.
- Cancelling keydown
- : Cancelling the keydown event now properly cancels any corresponding keyup/keypress events, per the DOM specification.
- Accessibility APIs for DHTML
- : Mozilla now allows DHTML authors to add role and state semantics to custom elements, and exposes that information via MSAA and ATK.
- DHTML Performance Fixes
- : A number of changes were made to significantly improve DHTML speed and smoothness.
#### Graphics
- SVG Support
- : SVG is W3C specification providing resolution-independent scalable vector graphics, along with a DOM. A technology preview of native SVG support is included in this release. Currently a subset of SVG 1.1 Full, missing functionality includes filters, declarative animation, and SVG defined fonts.
- `<canvas>` Support
- : `<canvas>` is a scriptable drawing surface for dynamically creating bitmap graphics. For a further introduction, see [Drawing Graphics with Canvas](/en-US/Drawing_Graphics_with_Canvas).
#### Miscellaneous
- Support HTTP/1.1 408 response code
- : A persistent connection is now correctly closed when a 408 response code (Request timeout) is received. The request is retried in a new connection.
- URIs always sent as UTF8
- : URIs are now always sent to the server as UTF8, regardless of the linking page's encoding. This fixes images and links on sites with non-ASCII filenames.
- XForms support
- : The [W3C's XML Forms](https://www.w3.org/MarkUp/Forms/) language allows writing complex forms in XML, and includes features that regular HTML forms do not have, such as client side validation against [XML Schema](https://www.w3.org/XML/Schema) and XML submission/retrieval. Support for XForms comes as an extension, see [Mozilla XForms Project Page](/en-US/docs/Archive/Web/XForms).
### New Extension Developer Features
- Hidden referrer column for history
- : Extensions can now access the referer information for pages stored in the browser history. This feature can be used to provide alternate history views and other useful functionality. [Firefox bug 128398](https://bugzil.la/128398)
- API for prioritizing HTTP connections
- : The Mozilla networking library now supports the prioritization of connections to a specific server using `nsISupportsPriority`. [Firefox bug 278531](https://bugzil.la/278531)
- API for managing user and UA stylesheets
- : Extensions can now register stylesheet URIs as additional user and UA stylesheets. This means extensions no longer have to try to edit `userContent.css` to add styling (say for XBL binding attachment) to web pages. See [Using the Stylesheet Service](/en-US/docs/Archive/Add-ons/Using_the_Stylesheet_Service).
- API for configuring proxies
- : It is now possible for extensions to easily override the proxy configuration without affecting user-visible preferences. See `nsIProtocolProxyService`, `nsIProtocolProxyFilter`, and `nsIProtocolProxyCallback`. [Firefox bug 282442](https://bugzil.la/282442)
- Dynamic Overlays
- : Loading of XUL overlays after the document has been displayed is now supported. See `nsIDOMXULDocument`. [Firefox bug 282103](https://bugzil.la/282103)
- ECMAScript for XML (E4X)
- : The Mozilla JavaScript engine now supports ECMAScript for XML (E4X), a draft ECMA standard that adds native XML datatypes to the language and provides operators for common XML operations. See [the ECMA specification](https://ecma-international.org/publications-and-standards/standards/ecma-357/). [Firefox bug 246441](https://bugzil.la/246441)
- Translucent Windows (Windows/Linux)
- : On Windows and Linux, XUL windows with a transparent background are now supported. This allows whatever is below the window to shine through the window background.
- Adding tokens to the User-Agent string
- : It is now possible for applications, extensions, and vendors to all add tokens to the User-Agent string (using default preferences) without overwriting each other.
See [documentation](/en-US/docs/Web/HTTP/Headers/User-Agent). [Firefox bug 274928](https://bugzil.la/274928)
- Toolkit chrome registry
- : Chrome registration has been significantly improved to use simple plaintext chrome registration manifests, and no longer keeps the chrome.rdf/overlayinfo cache.
See [Chrome Registration](/en-US/docs/Mozilla/Chrome_Registration).
- Extension Manager
- : Following are the new features:
- It is now possible to have Extensions outside the profile and application Extensions directories.
- Installing extensions can now be done by dropping an XPI into the profile or application Extensions directory.
- Uninstalling an Extension now involves deleting its folder from the profile or application Extensions directory.
- New Preferences bindings
- : These [new bindings](https://forums.mozillazine.org/viewtopic.php?t=263028) make it easier to create preferences windows for extensions. The new preferences windows support instant-apply behavior, which is enabled by default on Mac and Linux.
- API for implementing new command-line switches
- : An API has been introduced so that extensions can easily handle complex command-line flags. This API will be stable and frozen for 1.1. See the interfaces `nsICommandLine` and `nsICommandLineHandler`.
- XTF Support
- : The eXtensible Tag Framework allows adding support for new namespaces using XPCOM components to Mozilla (written in JavaScript or C++). See [XTF Home Page](https://web.archive.org/web/20070527160710/http://www.croczilla.com/xtf).
### New Browser Features
#### Improved Preferences
- Instant Apply behavior on Linux and Mac
- : Changes made in the Preferences window now apply immediately, in line with typical behavior in other Mac OS X and GNOME applications. This changes conforms with the Apple and GNOME Human Interface Guidelines.
- Searchable download actions manager
- : It is possible to search the Download Actions manager by file extension or description.
- Searchable cookie manager
- : Cookies can be searched by hostname/domain and cookie name, and are organized by hostname in a tree format instead of a flat list.
#### Deployment
- Firefox MSI package
- : The new MSI installation package facilitates distributed installation and provides greater flexibility to network administrators wanting to deploy Firefox in a corporate environment.
- Support for profile "temp" directory on local filesystem
- : It is now possible to store the network cache (copies of visited webpages) and the XUL fastload cache (precompiled user interface code) on a local disk, while keeping the rest of the profile data on a network drive. This will increase performance and reduce network traffic for users in a network environment.
#### Other
- "Sanitize" privacy feature
- : The "Sanitize" feature provides an easy way to quickly remove browsing history, cookies, cache, saved form information, and other personal data. The items to be removed can be customized, and the feature can be activated using either a keyboard shortcut or through a menu item.
- Image thumbnails as tab icons
- : When viewing images, tab icons now display thumbnails of the displayed image.
- Fast back (and forward)
- : This very experimental feature allows much faster session history navigation. The feature is off by default but can be enabled for testing purposes by setting the `browser.sessionhistory.max_viewers` preference to a nonzero number.
- Anonymous FTP login failure behavior
- : FTP users are now prompted to input a name and password if anonymous access fails.
- CSS at-rule for matching on site/document URL
- : The new `@-moz-document` rule gives users the ability to match page objects per-site, using CSS. This makes it possible to include site-specific rules in user style sheets (userContent.css). [David Baron's post to `www-style`](https://lists.w3.org/Archives/Public/www-style/2004Aug/0135.html) explains how the rule can be used.
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases/1.5 | data/mdn-content/files/en-us/mozilla/firefox/releases/1.5/changing_the_priority_of_http_requests/index.md | ---
title: Changing the Priority of HTTP Requests (Non-Standard)
slug: Mozilla/Firefox/Releases/1.5/Changing_the_priority_of_HTTP_requests
page-type: guide
---
{{FirefoxSidebar}}
> **Warning:** The approach described in this topic is non-standard, and not recommended.
>
> The best way to request resources over HTTP is to use [`fetch()`](/en-US/docs/Web/API/fetch), which allows you to specify the priority in [`Request.priority`](/en-US/docs/Web/API/Request/priority).
> You can also set the HTTP priority on [`HTMLLinkElement`](/en-US/docs/Web/API/HTMLLinkElement/fetchPriority), [`HTMLIFrameElement`](/en-US/docs/Web/API/HTMLIFrameElement), and [`HTMLImageElement`](/en-US/docs/Web/API/HTMLImageElement/fetchPriority) elements (and associated tags) using the `fetchpriority` attribute.
In [Firefox 1.5](/en-US/docs/Mozilla/Firefox/Releases/1.5), an API was added to support changing the priority of [HTTP](/en-US/docs/Web/HTTP) requests. Prior to this, there was no way to directly indicate that a request was of a different priority. The API is defined in `nsISupportsPriority`, but is defined in very generic terms so that any object can implement this interface to enable the concept of priority. This article deals specifically with using that interface to change the priority of HTTP requests.
At the time of this writing, changing the priority of an HTTP request only affects the order in which connection attempts are made. This means that the priority only has an effect when there are more connections (to a server) than are allowed.
The examples in this document are all written in [JavaScript](/en-US/docs/Web/JavaScript) using XPCOM.
It should be noted that the value of the `priority` attribute follows UNIX conventions, with smaller numbers (including negative numbers) having higher priority.
## Accessing priority from an nsIChannel
To change the priority of an HTTP request, you need access to the `nsIChannel` that the request is being made on. If you do not have an existing channel, then you can create one as follows:
```js
var ios = Components.classes["@mozilla.org/network/io-service;1"].getService(
Components.interfaces.nsIIOService,
);
var ch = ios.newChannel("https://www.example.com/", null, null);
```
Once you have an `nsIChannel`, you can access the priority as follows:
```js
if (ch instanceof Components.interfaces.nsISupportsPriority) {
ch.priority = Components.interfaces.nsISupportsPriority.PRIORITY_LOWEST;
}
```
For convenience, the interface defines several standard priority values that you can use, ranging from `PRIORITY_HIGHEST` to `PRIORITY_LOWEST`.
## Getting an nsIChannel from XMLHttpRequest
If you are programming in [JavaScript](/en-US/docs/Web/JavaScript), you will probably want to use [XMLHttpRequest](/en-US/docs/Web/API/XMLHttpRequest), a much higher level abstraction of an HTTP request. You can access the `channel` member of an [XMLHttpRequest](/en-US/docs/Web/API/XMLHttpRequest) once you have called the `open` method on it, as follows:
```js
var req = new XMLHttpRequest();
req.open("GET", "https://www.example.com", false);
if (req.channel instanceof Components.interfaces.nsISupportsPriority) {
req.channel.priority =
Components.interfaces.nsISupportsPriority.PRIORITY_LOWEST;
}
req.send(null);
```
> **Note:** This example uses a synchronous [XMLHttpRequest](/en-US/docs/Web/API/XMLHttpRequest), which you should not use in practice.
## Adjusting priority
`nsISupportsPriority` includes a convenience method named `adjustPriority`. You should use this if you want to alter the priority of a request by a certain amount. For example, if you would like to make a request have slightly higher priority than it currently has, you could do the following:
```js
// assuming we already have a nsIChannel from above
if (ch instanceof Components.interfaces.nsISupportsPriority) {
ch.adjustPriority(-1);
}
```
Remember that lower numbers mean higher priority, so adjusting by a negative number will serve to increase the request's priority.
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/53/index.md | ---
title: Firefox 53 for developers
slug: Mozilla/Firefox/Releases/53
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
Firefox 53 was released on April 19, 2017. This article lists key changes that are useful not only for web developers but also for Firefox and Gecko developers, as well as add-on developers.
## Changes for Web developers
### Developer Tools
- Avoid scrolling latency on highlighters given by APZ ([Firefox bug 1312103](https://bugzil.la/1312103)).
- Added option to [copy the full CSS path](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_html/index.html#copy-css-path) of an element ([Firefox bug 1323700](https://bugzil.la/1323700)).
- Devtools support for css-color-4 ([Firefox bug 1310681](https://bugzil.la/1310681)).
- Markup view: add a visual hint between opening and closing tags of a collapsed node ([Firefox bug 1323193](https://bugzil.la/1323193)).
### CSS
#### New features
- The `mask-*` longhand properties (see [CSS Masks](/en-US/docs/Web/CSS/CSS_masking)) are all supported and available by default (see [Firefox bug 1251161](https://bugzil.la/1251161)).
- Added {{cssxref("caret-color")}} property ([Firefox bug 1063162](https://bugzil.la/1063162)).
- Implemented the {{cssxref("place-items")}}/{{cssxref("place-self")}}/{{cssxref("place-content")}} shorthands ([Firefox bug 1319958](https://bugzil.la/1319958)).
- Added `flow-root` value to {{cssxref("display")}} property ([Firefox bug 1322191](https://bugzil.la/1322191)).
- {{cssxref("tab-size", "-moz-tab-size")}} now accepts {{cssxref("<length>")}} values ([Firefox bug 943918](https://bugzil.la/943918)), and is now animatable ([Firefox bug 1308110](https://bugzil.la/1308110)).
- {{cssxref("mask-mode")}}:luminance doesn't work on gradient masks ([Firefox bug 1346265](https://bugzil.la/1346265)).
- \[css-grid] FR Unit in {{cssxref("grid-template-rows")}} not filling viewport ([Firefox bug 1346699](https://bugzil.la/1346699)).
- flex items aren't sorted according to "order", if they're separated by an abspos sibling ([Firefox bug 1345873](https://bugzil.la/1345873)).
#### Other changes
- Enable mask longhands on SVG elements ([Firefox bug 1319667](https://bugzil.la/1319667)).
- \[css-grid] Fixed: `align-self`/`justify-self:stretch`/`normal` doesn't work on `<table>` grid items ([Firefox bug 1316051](https://bugzil.la/1316051)).
- Fixed: `clip-path: circle()` with large reference box and percentage radius does not render correctly ([Firefox bug 1324713](https://bugzil.la/1324713).
- When applying a {{cssxref("text-transform")}} value of `uppercase` to Greek text, the accent on the disjunctive eta (ή) is no longer removed (see [Firefox bug 1322989](https://bugzil.la/1322989)).
- The availability of the `contents` value of {{cssxref("display")}} was controlled through the `layout.css.display-contents.enabled` pref. In Firefox 53, this pref has been removed altogether, so the value will always be available and can no longer be disabled ([Firefox bug 1295788](https://bugzil.la/1295788)).
### JavaScript
- ECMAScript 2015 semantics for the {{jsxref("Function.name")}} properties have been implemented. This includes inferred names on anonymous functions (`var foo = function() {}`) ([Firefox bug 883377](https://bugzil.la/883377)).
- ECMAScript 2015 semantics for closing iterators have been implemented. This affects the [`for...of`](/en-US/docs/Web/JavaScript/Reference/Statements/for...of) loop, for example ([Firefox bug 1147371](https://bugzil.la/1147371)).
- The [Template Literal Revision proposal](https://tc39.es/proposal-template-literal-revision/) that [lifts escape sequence restrictions on tagged template literals](/en-US/docs/Web/JavaScript/Reference/Template_literals#tagged_templates_and_escape_sequences) has been implemented ([Firefox bug 1317375](https://bugzil.la/1317375)).
- The static `length` property of {{jsxref("TypedArray")}} objects was changed from 3 to 0 as per ES2016 ([Firefox bug 1317306](https://bugzil.la/1317306)).
- {{jsxref("SharedArrayBuffer")}} can now be used in {{jsxref("DataView")}} objects ([Firefox bug 1246597](https://bugzil.la/1246597)).
- In earlier versions of the specification, {{jsxref("SharedArrayBuffer")}} objects needed to be explicitly transferred during [structured cloning](/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm). In the new specification, they aren't [transferable objects](/en-US/docs/Web/API/Web_Workers_API/Transferable_objects) anymore and thus must not be in the transfer list. The new behavior used to present a console warning only, but will now throw an error ([Firefox bug 1302037](https://bugzil.la/1302037)).
- The {{jsxref("ArrayBuffer")}} length is now limited to {{jsxref("Number.MAX_SAFE_INTEGER")}} (>= 2 \*\* 53) ([Firefox bug 1255128](https://bugzil.la/1255128)).
- {{jsxref("Error")}} and other native error object prototypes like {{jsxref("RangeError")}} etc. are now ordinary objects instead of proper Error objects. (In particular, `Object.prototype.toString.call(Error.prototype)` is now `"[object Object]"` instead of `"[object Error]"`.) ([Firefox bug 1213341](https://bugzil.la/1213341)).
### Events
- CSS Transitions: The {{domxref("Element/transitionstart_event", "transitionstart")}}, {{domxref("Element/transitionrun_event", "transitionrun")}}, and {{domxref("Element/transitioncancel_event", "transitioncancel")}} events have been implemented (see [Firefox bug 1264125](https://bugzil.la/1264125) and [Firefox bug 1287983](https://bugzil.la/1287983)).
- The {{domxref("CompositionEvent.CompositionEvent", "CompositionEvent")}} constructor has been implemented (see [Firefox bug 1002256](https://bugzil.la/1002256)).
- The {{domxref("MouseEvent.x")}} and {{domxref("MouseEvent.y")}} aliases of {{domxref("MouseEvent.clientX")}}/{{domxref("MouseEvent.clientY")}} have been implemented (see [Firefox bug 424390](https://bugzil.la/424390)).
- The {{domxref("Element/auxclick_event", "auxclick")}} event and corresponding event handler have been implemented (see [Firefox bug 1304044](https://bugzil.la/1304044)).
- The {{domxref("Element/transitioncancel_event", "transitioncancel")}} event is now fired after a [transition](/en-US/docs/Web/CSS/CSS_transitions) is cancelled.
### DOM
- The {{domxref("HTMLAnchorElement/pathname", "pathname")}} and {{domxref("HTMLAnchorElement/search", "search")}} properties of links (like for {{HTMLElement("a")}} and {{HTMLELement("link")}} elements' interfaces previously returned the wrong parts of the URL. For example, for a URL of `http://z.com/x?a=true&b=false`, `pathname` would return "`/x?a=true&b=false"` and `search` would return "", rather than "`/x`" and "`?a=true&b=false"` respectively. This has now been fixed ([Firefox bug 1310483](https://bugzil.la/1310483)).
- The {{domxref("URLSearchParams.URLSearchParams", "URLSearchParams()")}} constructor now accepts a string or sequence of strings as an init object ([Firefox bug 1330678](https://bugzil.la/1330678)).
- The {{domxref("Selection.setBaseAndExtent()")}} method of the [Selection API](/en-US/docs/Web/API/Selection) is now implemented (see [Firefox bug 1321623](https://bugzil.la/1321623)).
- The ["fakepath"](https://html.spec.whatwg.org/multipage/forms.html#fakepath-srsly) addition to `file` type {{htmlelement("input")}} `values` has been implemented in Gecko, giving it parity with other browsers (see [Firefox bug 1274596](https://bugzil.la/1274596)).
- {{domxref("Node.getRootNode()")}} has been implemented, replacing the deprecated `Node.rootNode` property ([Firefox bug 1269155](https://bugzil.la/1269155)).
- Own properties of {{domxref("Plugin")}} and {{domxref("PluginArray")}} objects are no longer enumerable ([Firefox bug 1270366](https://bugzil.la/1270366)).
- Named properties of {{domxref("MimeTypeArray")}} objects are no longer enumerable ([Firefox bug 1270364](https://bugzil.la/1270364)).
- The [Permissions API](/en-US/docs/Web/API/Permissions_API) now has a new permission name available — `persistent-storage` — as used when making a {{domxref("Permissions.query()")}} (see [Firefox bug 1270038](https://bugzil.la/1270038)). This allows an origin to use a persistent box (i.e., [persistent storage](https://storage.spec.whatwg.org/#persistence)) for its storage, as per the [Storage API](https://storage.spec.whatwg.org/).
- The {{domxref("Performance.timeOrigin")}} property has been implemented ([Firefox bug 1313420](https://bugzil.la/1313420)).
### Workers and service workers
- The [Network Information API](/en-US/docs/Web/API/Network_Information_API) is now available in workers (see [Firefox bug 1323172](https://bugzil.la/1323172)).
- [Server-sent events](/en-US/docs/Web/API/Server-sent_events) can now be used in workers (see [Firefox bug 1267903](https://bugzil.la/1267903)).
- {{domxref("ExtendableEvent.waitUntil", "ExtendableEvent.waitUntil()")}} can now be called asynchronously (see [Firefox bug 1263304](https://bugzil.la/1263304)).
### WebGL
- The {{domxref("WEBGL_compressed_texture_astc")}} WebGL extension has been implemented ([Firefox bug 1250077](https://bugzil.la/1250077)).
- The {{domxref("WEBGL_debug_renderer_info")}} WebGL extension is now enabled by default ([Firefox bug 1336645](https://bugzil.la/1336645)).
### Audio, video, and media
#### General
- Beginning in **Firefox 53 for Android**, decoding of media is handled out-of-process for improved performance on multi-core systems ([Firefox bug 1333323](https://bugzil.la/1333323)).
#### Media elements
- The {{domxref("HTMLMediaElement.play()")}} method, used to begin playback of media in any media element, now returns a {{jsxref("Promise")}} which is fulfilled when playback begins and is rejected if an error occurs ([Firefox bug 1244768](https://bugzil.la/1244768)).
#### Web Audio API
- The {{domxref("AudioScheduledSourceNode")}} interface has been added and the {{domxref("AudioBufferSourceNode")}}, {{domxref("ConstantSourceNode")}}, and {{domxref("OscillatorNode")}} interfaces are now based on it ([Firefox bug 1324568](https://bugzil.la/1324568)).
- All the different audio node types have had constructors added to them ([Firefox bug 1322883](https://bugzil.la/1322883)).
#### WebRTC
- The {{domxref("RTCPeerConnection")}} methods {{domxref("RTCPeerConnection.createOffer", "createOffer()")}} and {{domxref("RTCPeerConnection.createAnswer", "createAnswer()")}} now return a {{jsxref("Promise")}} that returns an object conforming to the `RTCSessionDescriptionInit` dictionary instead of returning an {{domxref("RTCSessionDescription")}} directly. Existing code will continue to work, but new code can be written more simply.
- Similarly, the {{domxref("RTCPeerConnection")}} methods {{domxref("RTCPeerConnection.setLocalDescription", "setLocalDescription()")}} and {{domxref("RTCPeerConnection.setRemoteDescription", "setRemoteDescription()")}} now accept as input an object conforming to the dictionary `RTCSessionDescriptionInit` dictionary. Existing code continues to work, but [can be simplified](/en-US/docs/Web/API/RTCPeerConnection/setLocalDescription#about_the_session_description_parameter).
- {{domxref("RTCPeerConnection.addIceCandidate()")}} now accepts as input an initialization object. This is compatible with existing code but allows new code to be written slightly more simply when used in tandem with the changes listed above ([Firefox bug 1263312](https://bugzil.la/1263312)).
- {{Glossary("DTMF")}} support is now enabled by default using {{domxref("RTCDTMFSender")}}. See [Using DTMF with WebRTC](/en-US/docs/Web/API/WebRTC_API/Using_DTMF) for more information on how this works.
### HTTP/Networking
- Gecko now has a pref available in `about:config` to allow users to set their default {{HTTPHeader("Referrer-Policy")}} — `network.http.referer.userControlPolicy` ([Firefox bug 1304623](https://bugzil.la/1304623)). Possible values are:
- 0 — `no-referrer`
- 1 — `same-origin`
- 2 — `strict-origin-when-cross-origin`
- 3 — `no-referrer-when-downgrade` (the default)
- Support for Next Protocol Negotiation (NPN) has been removed in favor of [Application-Layer Protocol Negotiation](https://en.wikipedia.org/wiki/Application-Layer_Protocol_Negotiation) (ALPN) — see [Firefox bug 1248198](https://bugzil.la/1248198).
- The {{httpheader("Large-Allocation")}} HTTP header is now available by default, and no longer hidden behind a pref ([Firefox bug 1331083](https://bugzil.la/1331083)).
### SVG
- Partly implemented {{domxref("SVGGeometryElement")}} interface ([Firefox bug 1239100](https://bugzil.la/1239100)).
## Removals from the web platform
### HTML/XML
- The `dom.details_element.enabled` pref — which controlled enabling/disabling {{htmlelement("details")}} and {{htmlelement("summary")}} element support in Firefox — has now been removed from `about:config`. These elements (first enabled by default in Firefox 49) can no longer be disabled. See [Firefox bug 1271549](https://bugzil.la/1271549).
- The `mozapp` attribute of the {{htmlelement("iframe")}} element /{{domxref("HTMLIFrameElement")}} interface has been removed — this was used to enable a Firefox OS app to be embedded in a mozilla-prefixed Browser API `<iframe>` ([Firefox bug 1310845](https://bugzil.la/1310845)).
- The `HTMLIFrameElement.setInputMethodActive()` method and `InputMethod` interface (used to set and manage IMEs on Firefox OS apps) has been removed ([Firefox bug 1313169](https://bugzil.la/1313169)).
### CSS
- Removed `-moz` prefixed variant of {{cssxref(":dir", ":dir()")}} pseudo-class ([Firefox bug 1270406](https://bugzil.la/1270406)).
- The `-moz` prefixed version of {{cssxref("text-align-last")}} got removed ([Firefox bug 1276808](https://bugzil.la/1276808)).
- Removed `-moz` prefixed variant of {{cssxref("calc", "calc()")}} method ([Firefox bug 1331296](https://bugzil.la/1331296)).
- The proprietary `-moz-samplesize` media fragment (added to aid in delivery of downsampled images to low memory Firefox OS devices; see [Firefox bug 854795](https://bugzil.la/854795)) has been removed ([Firefox bug 1311246](https://bugzil.la/1311246)).
### JavaScript
- The non-standard {{jsxref("ArrayBuffer.slice()")}} method has been removed (but the standardized version {{jsxref("ArrayBuffer.prototype.slice()")}} is kept, see [Firefox bug 1313112](https://bugzil.la/1313112)).
### APIs
- The Wi-Fi information API, Speaker Manager API, and Tethering API, and Settings API] have been removed from the platform (see [Firefox bug 1313788](https://bugzil.la/1313788), [Firefox bug 1317853](https://bugzil.la/1317853), [Firefox bug 1313789](https://bugzil.la/1313789), and [Firefox bug 1313155](https://bugzil.la/1313155) respectively).
### Other
- The `legacycaller` has been removed from the {{domxref("HTMLEmbedElement")}} and {{domxref("HTMLObjectElement")}} interfaces ([Firefox bug 909656](https://bugzil.la/909656)).
## Changes for add-on and Mozilla developers
### WebExtensions
New APIs:
- [`browsingData`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/browsingData)
- [`identity`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/identity)
- [`contextualIdentities`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/contextualIdentities)
Enhanced APIs:
- [`storage.sync`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/storage/sync)
- `page_action`, `browser_action`, `password`, `tab` [context types](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/menus/ContextType) in [`contextMenus`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/menus)
- [`webRequest.onBeforeRequest`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/webRequest/onBeforeRequest) now supports `requestBody`
- [`tabs.insertCSS`](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/tabs/insertCSS) now supports `cssOrigin`, enabling you to insert user style sheets.
### JavaScript code modules
- The asynchronous [AddonManager APIs]((/en-US/docs/Mozilla/Add-ons/Add-on_Manager/AddonManager) now support {{jsxref("Promise", "Promises")}} as well as callbacks ([Firefox bug 987512](https://bugzil.la/987512).
## Older versions
{{Firefox_for_developers(52)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/97/index.md | ---
title: Firefox 97 for developers
slug: Mozilla/Firefox/Releases/97
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 97 that affect developers. Firefox 97 was released on February 8, 2022.
## Changes for web developers
### HTML
No notable changes
### CSS
- The CSS units `cap` and `ic` are now supported for use with {{cssxref("<length>")}} and {{cssxref("<length-percentage>")}} data types.
For more information, see [Firefox bug 1702924](https://bugzil.la/1702924) and [Firefox bug 1531223](https://bugzil.la/1531223).
- The CSS property `color-adjust` has been renamed to {{cssxref("print-color-adjust")}} to match the relevant specification.
The `color-adjust` shorthand name is deprecated.
See [Firefox bug 747595](https://bugzil.la/747595) for details.
- CSS cascade layers are now available by default. The [`@layer`](/en-US/docs/Web/CSS/@layer) rule declares a cascade layer, which allows declaration of styles and can be imported via the [`@import`](/en-US/docs/Web/CSS/@import) rule using the `layer()` function. See [Firefox bug 1699217](https://bugzil.la/1699217) for more details.
- The global CSS keyword {{cssxref("revert-layer")}} has been added to allow rolling back of property values in one cascade layer to the matching rules in the previous cascade layer. This keyword can be applied on any property, including the CSS shorthand property {{cssxref("all")}}. For more information, see [Firefox bug 1699220](https://bugzil.la/1699220).
- The CSS [`scrollbar-gutter`](/en-US/docs/Web/CSS/scrollbar-gutter) property is now supported. This gives developers control over reserved space for the scrollbar, preventing unwanted layout changes as the content grows.
See [Firefox bug 1715112](https://bugzil.la/1715112) for more details.
### JavaScript
No notable changes
### SVG
- The SVG {{SVGAttr('d')}} attribute, used to define a path to be drawn, can now be used as a property in CSS.
It accepts the values [path()](/en-US/docs/Web/CSS/path) or `none`. (See [Firefox bug 1744599](https://bugzil.la/1744599) for details.)
#### Removals
- A number of `SVGPathSeg` APIs are now disabled by default behind a preference, and are expected to be removed in future revisions.
This includes: `SVGPathSegList`, [SVGPathElement.getPathSegAtLength()](/en-US/docs/Web/API/SVGPathElement), `SVGAnimatedPathData`.
(See [Firefox bug 1388931](https://bugzil.la/1388931) for more details.)
### APIs
- `AnimationFrameProvider` is now available in a [`DedicatedWorkerGlobalScope`](/en-US/docs/Web/API/DedicatedWorkerGlobalScope). This means the [`requestAnimationFrame`](/en-US/docs/Web/API/window/requestAnimationFrame) and [`cancelAnimationFrame`](/en-US/docs/Web/API/Window/cancelAnimationFrame) methods can be used within a dedicated worker.
(See [Firefox bug 1388931](https://bugzil.la/1388931) for more details.)
#### DOM
- The reason for an abort signal can now be set using {{domxref("AbortController.abort()")}} (or {{domxref("AbortSignal.abort_static", "AbortSignal.abort()")}}), and will be available in the {{domxref("AbortSignal.reason")}} property.
This reason defaults to being an "AbortError" {{domxref("DOMException")}}.
The reason can be thrown or handled via promise rejection as appropriate.
([Firefox bug 1737771](https://bugzil.la/1737771)).
- The convenience method {{domxref("AbortSignal.throwIfAborted()")}} can be used to check if a signal has been aborted, and if so throw the {{domxref("AbortSignal.reason()")}}.
This makes it easier for developers to handle abort signals in code where you can't simply pass the signal to an abortable method. ([Firefox bug 1745372](https://bugzil.la/1745372)).
### WebDriver conformance (Marionette)
- `Marionette:Quit` accepts a new boolean parameter, `safeMode`, to restart Firefox in safe mode ([Firefox bug 1144075](https://bugzil.la/1144075)).
- Improved stability for `WebDriver:NewSession` and `WebDriver:NewWindow` when waiting for the current or initial document to be loaded ([Firefox bug 1739369](https://bugzil.la/1739369), [Firefox bug 1747359](https://bugzil.la/1747359)).
## Changes for add-on developers
- `cookieStoreId` in {{WebExtAPIRef("tabs.query")}} supports an array of strings. This enables queries to match tabs against more than one cookie store ID ([Firefox bug 1730931](https://bugzil.la/1730931)).
- `cookieStoreId` added to {{WebExtAPIRef("contentScripts.register")}}. This enables extensions to register container-specific content scripts ([Firefox bug 1470651](https://bugzil.la/1470651)).
## Older versions
{{Firefox_for_developers(96)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/65/index.md | ---
title: Firefox 65 for developers
slug: Mozilla/Firefox/Releases/65
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 65 that will affect developers. Firefox 65 was released on January 29, 2019.
## Changes for web developers
### Developer tools
- The [Flexbox inspector](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_flexbox_layouts/index.html) is now enabled by default.
- Support has been added to the [JavaScript Debugger](https://firefox-source-docs.mozilla.org/devtools-user/debugger/index.html) for XHR Breakpoints ([Firefox bug 821610](https://bugzil.la/821610)).
- Right-click on an item in the accessibility tree from the Accessibility viewer to [print it as JSON](https://firefox-source-docs.mozilla.org/devtools-user/accessibility_inspector/index.html#print-accessibility-tree-to-json) to the JSON viewer.
- The [color contrast](https://firefox-source-docs.mozilla.org/devtools-user/accessibility_inspector/index.html#color-contrast) display of the Accessibility Picker has been updated so that if a text's background is complex (e.g. a gradient or complex image), it shows a range of color contrast values.
- The Headers tab of the [Network Monitor](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/index.html) now displays the Referrer Policy for the selected request ([Firefox bug 1496742](https://bugzil.la/1496742)).
- When displaying stack traces (e.g. in console logs or the JavaScript debugger), calls to framework methods are identified and collapsed by default, making it easier to home in on your code.
- In the same fashion as native terminals, you can now use reverse search to find entries in your JavaScript console history (`F9` on Windows/Linux or `Ctrl` + `R` on macOS, then type a search term, followed by `Ctrl` + `R`/`Ctrl` + `S` to toggle through results).
- The JavaScript console's `$0` shortcut (references the currently inspected element on the page) now has autocomplete available, so for example you could type `$0.te` to get autocomplete suggestions for properties like `$0.textContent`.
- The edits you make in the Rules view of the Inspector are now listed in the Changes panel ([Firefox bug 1503920](https://bugzil.la/1503920)).
### HTML
- Events are now dispatched on disabled HTML elements, i.e. {{htmlelement("button")}}, {{htmlelement("fieldset")}}, {{htmlelement("input")}}, {{htmlelement("select")}}, and {{htmlelement("textarea")}} elements with `disabled` attributes set on them ([Firefox bug 329509](https://bugzil.la/329509)).
- Removing the `src` attribute of an {{htmlelement("iframe")}} element now causes `about:blank` to be loaded into it, giving it parity with Chrome and Safari ([Firefox bug 1507842](https://bugzil.la/1507842)). Previously removing `src` had no effect on the `iframe` content.
- We have added support for the [`referrerpolicy`](/en-US/docs/Web/HTML/Element/script#referrerpolicy) attribute on {{htmlelement("script")}} elements ([Firefox bug 1460920](https://bugzil.la/1460920)).
### CSS
- The {{cssxref("image-rendering")}} property's `crisp-edges` value has now been unprefixed ([Firefox bug 1496617](https://bugzil.la/1496617)).
- A {{cssxref("scrollbar-color")}} value of `auto` now resolves to `auto`, rather than two colors ([Firefox bug 1501418](https://bugzil.la/1501418)).
- The `break-*` properties have been implemented, and the legacy `page-break-*` properties have been aliased to them ([Firefox bug 775618](https://bugzil.la/775618)):
- {{cssxref("break-before")}} is now an alias for {{cssxref("page-break-before")}}.
- {{cssxref("break-after")}} is now an alias for {{cssxref("page-break-after")}}.
- {{cssxref("break-inside")}} is now an alias for {{cssxref("page-break-inside")}}.
- The {{cssxref("overflow-wrap")}} property's `anywhere` value has been implemented ([Firefox bug 1505786](https://bugzil.la/1505786)).
- The new step position keywords `jump-start`, `jump-end`, `jump-none`, and `jump-both` — usable inside the [`steps()` timing function](/en-US/docs/Web/CSS/easing-function#step_easing_function) — have been implemented ([Firefox bug 1496619](https://bugzil.la/1496619)). This also coincides with the removal of the `frames()` timing function, which was the previous way of implementing such functionality, now deprecated.
- Some new {{cssxref("appearance", "-webkit-appearance")}} values have been added, for compatibility with other browsers. In particular:
- `meter`, which is now used as the default value for {{htmlelement("meter")}} elements in UA stylesheets. The existing value `meterbar` is now an alias for `meter` ([Firefox bug 1501483](https://bugzil.la/1501483)).
- `progress-bar`, which is now used as the default value for {{htmlelement("progress")}} elements in UA stylesheets. The existing value `progressbar` is now an alias for `progress-bar` ([Firefox bug 1501506](https://bugzil.la/1501506)).
- `textarea`, which is now used as the default value for {{htmlelement("textarea")}} elements in UA stylesheets. The existing value `textfield-multiline` is now an alias for `textarea` ([Firefox bug 1507905](https://bugzil.la/1507905)).
- The behavior of {{cssxref("user-select")}} has been changed to make it align more with other browsers ([Firefox bug 1506547](https://bugzil.la/1506547)). Specifically:
- `user-select: all` set on an element no longer overrides other values of `user-select` set on children of that element. So for example in the following snippet:
```html
<div style="-webkit-user-select: all">
All
<div style="-webkit-user-select: none">None</div>
</div>
```
The `<div>` with `none` set on it is now non-selectable. Previously this value would have been overridden by the `all` value set on the parent element.
- non-`contenteditable` elements nested inside `contenteditable` elements are now selectable.
- `user-select` now behaves consistently inside and outside shadow DOM.
- The proprietary `-moz-text` value has been removed.
- CSS environment variables (the {{cssxref("env", "env()")}} function) have been implemented ([Firefox bug 1462233](https://bugzil.la/1462233)).
#### Removals
- The `layout.css.shape-outside.enabled` pref has been removed; {{cssxref("shape-outside")}}, {{cssxref("shape-margin")}}, and {{cssxref("shape-image-threshold")}} can no longer be disabled in `about:config` ([Firefox bug 1504387](https://bugzil.la/1504387)).
- Several Firefox-only values of the {{cssxref("user-select")}} property have been removed — `-moz-all`, `-moz-text`, `tri-state`, `element`, `elements`, and `toggle`. See [Firefox bug 1492958](https://bugzil.la/1492958) and [Firefox bug 1506547](https://bugzil.la/1506547).
- As mentioned above, the `frames()` timing function has been removed ([Firefox bug 1496619](https://bugzil.la/1496619)).
### SVG
_No changes._
### JavaScript
- {{jsxref("Intl/RelativeTimeFormat", "Intl.RelativeTimeFormat")}} is now supported ([Firefox bug 1504334](https://bugzil.la/1504334)).
- Strings now have a maximum {{jsxref("String/length","length","","1")}} of `2**30 - 2` (\~1GB) instead of `2**28 - 1` (\~256MB) ([Firefox bug 1509542](https://bugzil.la/1509542)).
- The {{jsxref("globalThis")}} property, which always refers to the top-level global object, has been implemented ([Firefox bug 1317422](https://bugzil.la/1317422)).
### APIs
#### New APIs
- {{domxref("Streams_API/Using_readable_streams", "Readable Streams", "", "1")}} have been enabled by default ([Firefox bug 1505122](https://bugzil.la/1505122)).
- The {{domxref("Storage_Access_API", "Storage Access API", "", "1")}} has been enabled by default ([Firefox bug 1513021](https://bugzil.la/1513021)).
#### DOM
- {{domxref("Performance.toJSON()")}} has been exposed to {{domxref("Web_Workers_API", "Web Workers", "", "1")}} ([Firefox bug 1504958](https://bugzil.la/1504958)).
- {{domxref("XMLHttpRequest")}} requests will now throw a `NetworkError` if the requested content type is a `Blob`, and the request method is not `GET` ([Firefox bug 1502599](https://bugzil.la/1502599)).
- The `-moz-` prefixed versions of many of the {{domxref("Fullscreen API", "", "", "1")}} features have been deprecated, and will now display deprecation warnings in the JavaScript console when encountered ([Firefox bug 1504946](https://bugzil.la/1504946)).
- {{domxref("createImageBitmap()")}} now supports SVG images ({{domxref("SVGImageElement")}}) as an image source ([Firefox bug 1500768](https://bugzil.la/1500768)).
#### DOM events
- Going forward, only one {{domxref("Window.open()")}} call is allowed per event ([Firefox bug 675574](https://bugzil.la/675574)).
- The [`keyup`](/en-US/docs/Web/API/Element/keyup_event) and [`keydown`](/en-US/docs/Web/API/Element/keydown_event) events are now fired during IME composition, to improve cross-browser compatibility for CJKT users ([Firefox bug 354358](https://bugzil.la/354358).
#### Web workers
- {{domxref("SharedWorkerGlobalScope.connect_event", "SharedWorkerGlobalScope.connect")}}'s event object is a {{domxref("MessageEvent")}} instance — its `data` property is now an empty string value rather than `null` ([Firefox bug 1508824](https://bugzil.la/1508824)).
#### Fetch and Service workers
- The {{domxref("Response.redirect_static", "Response.redirect()")}} method now correctly throws a `TypeError` if a non-valid URL is specified as the first parameter ([Firefox bug 1503276](https://bugzil.la/1503276)).
- The {{domxref("ServiceWorkerContainer.register()")}} and {{domxref("WorkerGlobalScope.importScripts()")}} (when used by a service worker) methods will now accept any files with a valid [JavaScript MIME type](/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types#textjavascript) ([Firefox bug 1354577](https://bugzil.la/1354577)).
- The {{domxref("FetchEvent.replacesClientId")}} and {{domxref("FetchEvent.resultingClientId")}} properties are now supported ([Firefox bug 1264177](https://bugzil.la/1264177)).
- The {{domxref("ServiceWorkerGlobalScope.messageerror_event", "ServiceWorkerGlobalScope.onmessageerror")}} and {{domxref("ServiceWorkerContainer.messageerror_event", "ServiceWorkerContainer.onmessageerror")}} handler properties have been implemented ([Firefox bug 1399446](https://bugzil.la/1399446)).
- The {{httpheader("Origin")}} header is no longer set on Fetch requests with a method of {{HTTPMethod("HEAD")}} or {{HTTPMethod("GET")}} ([Firefox bug 1508661](https://bugzil.la/1508661)).
#### Media, Web Audio, and WebRTC
- The {{domxref("WebRTC API", "WebRTC", "", "1")}} {{domxref("RTCIceCandidateStats")}} dictionary has been updated according to the latest spec changes ([Firefox bug 1324788](https://bugzil.la/1324788), [Firefox bug 1489040](https://bugzil.la/1489040); RTCIceCandidateStats has been updated to the latest spec for more details on exactly what has changed).
- The {{domxref("MediaRecorder")}} `pause` and `resume` events (and their corresponding event handler properties were not previously implemented, even though compatibility tables claimed they had been. They have now been implemented ([Firefox bug 1458538](https://bugzil.la/1458538), [Firefox bug 1514016](https://bugzil.la/1514016)).
#### Canvas and WebGL
- The {{domxref("WebGL API", "WebGL", "", "1")}} {{domxref("EXT_texture_compression_bptc")}} and {{domxref("EXT_texture_compression_rgtc")}} texture compression extensions have been exposed to WebGL1 and WebGL2 contexts ([Firefox bug 1507263](https://bugzil.la/1507263)).
#### Removals
- [Mutation events](/en-US/docs/Web/API/MutationEvent) have been disabled in shadow trees ([Firefox bug 1489858](https://bugzil.la/1489858)).
- The non-standard {{domxref("MediaStream")}} property `currentTime` has been removed ([Firefox bug 1502927](https://bugzil.la/1502927)).
- The `dom.webcomponents.shadowdom.enabled` and `dom.webcomponents.customelements.enabled` prefs have been removed — Shadow DOM and Custom Elements can no longer be disabled in `about:config` ([Firefox bug 1503019](https://bugzil.la/1503019)).
- The non-standard DOM `text` event — fired to notify the browser editor UI of IME composition string data and selection range — has been removed ([Firefox bug 1288640](https://bugzil.la/1288640)).
- The {{domxref("Element/keypress_event", "keypress")}} event is no longer fired for [non-printable keys](</en-US/docs/Web/API/KeyboardEvent/keyCode#non-printable_keys_(function_keys)>) ([Firefox bug 968056](https://bugzil.la/968056)), except for the `Enter` key, and the `Shift` + `Enter` and `Ctrl` + `Enter` key combinations (these were kept for cross-browser compatibility purposes).
### Security
- Additional CORS restrictions are now being enforced on allowable request headers ([Firefox bug 1483815](https://bugzil.la/1483815), see also [whatwg fetch issue 382: CORS-safelisted request headers should be restricted according to RFC 7231](https://github.com/whatwg/fetch/issues/382) for more details).
### Networking
_No changes._
### Plugins
_No changes._
### WebDriver conformance (Marionette)
#### API changes
- `WebDriver:ElementSendKeys` now handles `<input type=file>` more relaxed for interactability checks, and allows those elements to be hidden without raising a `not interactable` error anymore. If a strict interactability check is wanted the capability `strictFileInteractability` can be used ([Firefox bug 1502864](https://bugzil.la/1502864)).
#### Bug fixes
- The window manipulation commands `WebDriver:FullscreenWindow`, `WebDriver:MinimizeWindow`, `WebDriver:MaximizeWindow`, and `WebDriver:SetWindowRect` have been made more stable ([Firefox bug 1492499](https://bugzil.la/1492499)). It means that under special conditions they don't cause an infinite hang anymore, but instead timeout after 5s if the requested window state cannot be reached ([Firefox bug 1521527](https://bugzil.la/1521527)).
- `WebDriver:ElementClick` now correctly calculates the center point of the element to click, which allows interactions with dimensions of 1x1 pixels ([Firefox bug 1499360](https://bugzil.la/1499360)).
#### Others
- For `unexpected alert open` errors more informative messages are provided ([Firefox bug 1502268](https://bugzil.la/1502268)).
### Other
- Support for [WebP](/en-US/docs/Glossary/WebP) images has been added ([Firefox bug 1294490](https://bugzil.la/1294490)).
- In addition, to facilitate cross-browser compatibility in certain situations the WebP MIMEType (`image/webp`) has been added to the standard HTTP Request {{httpheader("Accept")}} header for HTML files ([Firefox bug 1507691](https://bugzil.la/1507691)).
- The AV1 codec is now supported by default on Windows ([Firefox bug 1452146](https://bugzil.la/1452146)).
## Changes for add-on developers
### API changes
#### Tabs
- The {{WebExtAPIRef("tabs", "tabs API", "", "1")}} has been enhanced to support tab successors — a tab can have a successor assigned to it, which is the ID of the tab that will be active once it is closed ([Firefox bug 1500479](https://bugzil.la/1500479), also see [this blog post](https://qiita.com/piroor/items/ea7e727735631c45a366) for more information). In particular:
- The {{WebExtAPIRef("tabs.Tab")}} type now has a `successorId` property, which can be used to store/retrieve the ID of the tab's successor.
- The {{WebExtAPIRef("tabs.onActivated")}} event listener's callback has a new parameter available, `previousTabId`, which contains the ID of the previous activated tab, if it is still open.
- The {{WebExtAPIRef("tabs.update()")}} function's `updateProperties` object has a new optional property available on it, `successorTabId`, so can be used to update it.
- `successorTabId` is also returned by functions like {{WebExtAPIRef("tabs.get()")}} and {{WebExtAPIRef("tabs.query()")}}.
- The new function `tabs.moveInSuccession()` allows manipulation of tab successors in bulk.
### Manifest changes
_No changes._
### Other
- The `headerURL`/`theme_frame` properties for [WebExtension themes](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/theme) are now supported on Firefox for Android ([Firefox bug 1429488](https://bugzil.la/1429488)).
## See also
- Hacks release post: [Firefox 65: WebP support, Flexbox Inspector, new tooling & platform updates](https://hacks.mozilla.org/2019/01/firefox-65-webp-flexbox-inspector-new-tooling/)
## Older versions
{{Firefox_for_developers(64)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/11/index.md | ---
title: Firefox 11 for developers
slug: Mozilla/Firefox/Releases/11
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
Firefox 11 shipped on March 13, 2012. This article provides information about the new features and key bugs fixed in this release, as well as links to more detailed documentation for both web developers and add-on developers.
## Changes for Web developers
### HTML
- The attributes `muted` and `loop` on {{HTMLElement("audio")}} and {{HTMLElement("video")}} elements have been implemented.
### DOM
- The {{domxref("element.outerHTML")}} property is now supported on HTML elements.
- [`XMLHttpRequest` supports HTML parsing](/en-US/docs/Web/API/XMLHttpRequest_API/HTML_in_XMLHttpRequest).
- Removed support for using the {{domxref("XMLHttpRequest")}} `responseType` and `withCredentials` attributes when performing synchronous requests. Attempting to do so throws an `NS_ERROR_DOM_INVALID_ACCESS_ERR` exception. This change has been proposed to the W3C for standardization.
- The new {{domxref("window.navigator.mozVibrate()")}} method lets you vibrate the device where supported; this is implemented as `mozVibrate()` on Gecko.
- {{domxref("window.navigator.mozApps")}} returns an [`Apps`](/en-US/docs/DOM/Apps) object you can use to install and manage [open web applications](/en-US/docs/Web/Progressive_web_apps).
- `MozBeforePaint` events are no longer fired. {{domxref("window.requestAnimationFrame", "mozRequestAnimationFrame()")}} consumers who used these should pass a callback function instead.
- Support for canceling animation frame requests has been added; {{domxref("window.requestAnimationFrame", "window.mozRequestAnimationFrame()")}} now returns a request ID value, which you can pass to {{domxref("window.cancelAnimationFrame", "window.mozCancelAnimationFrame()")}} to cancel the request.
- Several {{domxref("Event")}} constructors (`Event`, HTML events, `UIEvent`, and `MouseEvent`) introduced in DOM4 specifications are now supported.
- The {{domxref("window.navigator.mozBattery", "Battery API")}} is now enabled by default.
- Support for the [`defaultMuted`](/en-US/docs/Web/API/HTMLMediaElement), [`loop`](/en-US/docs/Web/API/HTMLMediaElement) and [`muted`](/en-US/docs/Web/API/HTMLMediaElement) properties on [`HTMLMediaElement`](/en-US/docs/Web/API/HTMLMediaElement) has been added.
- Calling {{domxref("Document/exitFullscreen")}} now restores the previously fullscreen element if some other element was in fullscreen mode when the current element's {{domxref("Element/requestFullScreen")}} method was called.
- The {{domxref("window.requestAnimationFrame", "window.mozRequestAnimationFrame()")}} method no longer supports a no-argument form. This form was not used much and is unlikely to become part of the standard.
- SVG-as-an-image can now be drawn into a canvas without [tainting the canvas](/en-US/docs/Web/HTML/CORS_enabled_image#what_is_a_.22tainted.22_canvas.3f).
- The non-standard `countryCode` property of the `GeoPositionAddress` interface has been removed; see `nsIDOMGeoPositionAddress`.
- [Server-sent events](/en-US/docs/Web/API/Server-sent_events) now support [CORS](/en-US/docs/Web/HTTP/CORS).
- In the past, when the user followed a link, the values set on the {{domxref("window.navigator")}} object were retained by the new page. Now a new `navigator` object is created for the new page. This makes Firefox behave like all other browsers.
### CSS
- the [`text-size-adjust`](/en-US/docs/Web/CSS/text-size-adjust) property is now supported
- [CSS3](/en-US/docs/CSS/CSS3) [Conditional Rules](/en-US/docs/CSS/CSS3#conditional_rules) are now better supported: nested statements can now be added to [@media](/en-US/docs/Web/CSS/@media), [@-moz-document](/en-US/docs/Web/CSS/@document). (See [CSS Syntax](/en-US/docs/Web/CSS/Syntax) and [CSS at-rules](/en-US/docs/Web/CSS/At-rule)).
### JavaScript
_No change._
### SVG
- The {{domxref("SVGSVGElement")}} DOM interface now support the `getElementById` method.
### WebSocket
- [WebSocket](/en-US/docs/Web/API/WebSockets_API) API now supports binary messages (see [Firefox bug 676439](https://bugzil.la/676439)).
- Both the protocol and the API has been updated to the latest draft of the specification and the API has been unprefixed (see [Firefox bug 666349](https://bugzil.la/666349) and [Firefox bug 695635](https://bugzil.la/695635)).
- Previously, messages sent and received using WebSockets in Firefox were limited to 16 MB in size; they may now be up to 2 GB (although memory capacity limitations may prevent them from being that large, Firefox supports it).
### IndexedDB
- The support for [IDBFactory.cmp()](/en-US/docs/Web/API/IDBFactory#cmp%28%29) has been added.
- An [IndexedDB key](/en-US/docs/Web/API/IndexedDB_API/Basic_Terminology#key) can also be of one of the following types: Date, Arrays and Float (and not only String and Integer).
- From now on, transactions are started when the transaction is created, not when the first request is placed; for example consider this:
```js
var trans1 = db.transaction("foo", READ_WRITE);
var trans2 = db.transaction("foo", READ_WRITE);
trans2.put("2", "key");
trans1.put("1", "key");
```
After the code is executed the object store should contain the value "2", since `trans2` should run after `trans1`.
- Previous to Firefox 11, object store {{domxref("IDBObjectStore.autoIncrement","autoIncrement")}} counters were shared across all object stores for a given database, whereas per spec each object store should have a separate counter. This is now fixed.
- It is now possible to {{domxref("IDBObjectStore.createIndex","create an index")}} with an empty `keyPath`.
- It is now possible to create a multi-entry index (see [`IDBObjectStore.createIndex` parameters](/en-US/docs/Web/API/IDBObjectStore/createIndex#parameters).)
- The {{domxref("IDBTransaction/abort_event", "abort")}} event now bubbles; in addition, an `onabort` handler has been added.
- IndexedDB can now be used to store files/blobs.
- IndexedDB now supports complex key paths, e.g. `foo.bar` to access property `bar` of property `foo`.
- IndexedDB can now accept an array as a `keyPath` when creating an {{domxref("IDBDatabase.createObjectStore()","object store")}} or an {{domxref("IDBObjectStore.createIndex()","index")}} ([Firefox bug 694138](https://bugzil.la/694138).)
### Network
- The change in Firefox 8 that removed support for double quote characters as delimiters for {{rfc(2231)}} and {{rfc(5987)}} has been reverted, as this broke some sites, including Outlook Web Access.
- The user agent string in HTTP headers now includes an identifier that [lets the server know if the Firefox accessing it is a phone or a tablet](/en-US/docs/Gecko_user_agent_string_reference#mobile_and_tablet_indicators).
### Developer tools
- The [Page Inspector](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/index.html) now offers a [3D view](https://firefox-source-docs.mozilla.org/devtools-user/3d_view/index.html) if your system supports [WebGL](/en-US/docs/Web/API/WebGL_API).
- The new [Style Editor](https://firefox-source-docs.mozilla.org/devtools-user/style_editor/index.html) provides a free-form way to edit and compose CSS style sheets in real-time.
- The [View Source feature](https://firefox-source-docs.mozilla.org/devtools-user/view_source/index.html) now uses the new HTML5 parser instead of the old HTML parser.
## Changes for Mozilla and add-on developers
### JavaScript code modules
#### NetUtil.jsm
- `readInputStreamToString()` has a new, optional, parameter to configure the character set interpretation while reading the input stream.
#### New JavaScript code modules
- [`source-editor.jsm`](/en-US/docs/JavaScript_code_modules/source-editor.jsm)
- : Provides a convenient, easy-to-use source code editor that you can use in your add-ons. This is the same editor used by _Scratchpad_ and other developer tools integrated into Firefox.
### Interface changes
- The `mozIAsyncHistory` interface has a new method `mozIAsyncHistory.isURIVisited()` to check if a URI has been visited.
- A new interface `mozIVisitStatusCallback` has been added to provide callback handling functionality for `mozIAsyncHistory.isURIVisited()`.
- The `nsIMacDockSupport` interface now supports adding a text badge to the application's icon in the Dock using its new `badgeText` attribute.
- In the `nsINavHistoryResultObserver` interface, you now need to implement `nsINavHistoryResultObserver.containerStateChanged()` instead of the obsolete `containerOpened()` and `containerClosed()` methods.
#### Removed interfaces
The following interfaces were implementation details that are no longer needed:
- `nsICharsetResolver`
- `nsIDOMNSElement`, see [bug707576](https://bugzil.la/707576), use `nsIDOMElement` instead.
### Theme-related changes
- The `omni.jar` file is now called [`omni.ja`](</en-US/docs/Mozilla/About_omni.ja_(formerly_omni.jar)>).
### Preference changes
- `ui.tooltipDelay`
- : Specifies the delay, in milliseconds, between the mouse cursor beginning to hover and the display of a tooltip.
### Build system changes
- The `--enable-tracejit` build option has been removed.
### Other changes
- Add-ons that have not been updated in a long time are no longer assumed to be compatible by default; this is currently add-ons that indicate a `maxVersion` of 4.0.
## See also
{{Firefox_for_developers('10')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/100/index.md | ---
title: Firefox 100 for developers
slug: Mozilla/Firefox/Releases/100
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 100 that will affect developers. Firefox 100 was released on May 3, 2022.
## Changes for web developers
### HTML
No notable changes.
### CSS
- CSS media features for [`dynamic-range`](/en-US/docs/Web/CSS/@media/dynamic-range) and [`video-dynamic-range`](/en-US/docs/Web/CSS/@media/video-dynamic-range) are now supported. You can now test whether a user agent or an output device supports the combination of brightness, contrast ratio, and color depth by using `dynamic-range` and in the video plane by using `video-dynamic-range` ([Firefox bug 1751217](https://bugzil.la/1751217)).
### JavaScript
No notable changes.
### HTTP
#### Removals
- The non-standard {{httpheader("Large-Allocation")}} HTTP header has been removed ([Firefox bug 1598759](https://bugzil.la/1598759)).
### APIs
- [`WritableStream`](/en-US/docs/Web/API/WritableStream), [`WritableStreamDefaultWriter`](/en-US/docs/Web/API/WritableStreamDefaultWriter), [`WritableStreamDefaultController`](/en-US/docs/Web/API/WritableStreamDefaultController), and [`ReadableStream.pipeTo()`](/en-US/docs/Web/API/ReadableStream/pipeTo) are now supported ([Firefox bug 1759597](https://bugzil.la/1759597)).
#### DOM
- Code can now use the static method [`AbortSignal.timeout()`](/en-US/docs/Web/API/AbortSignal/timeout_static).
This returns an {{domxref("AbortSignal")}} that can be used to automatically abort an operation with `TimeoutError` after a specified time ([Firefox bug 1753309](https://bugzil.la/1753309)).
### WebAssembly
- WebAssembly now supports exceptions that can be thrown and caught in either WebAssembly or JavaScript (or some other runtime), crossing between the environment boundaries if not handled.
The JavaScript representations of WebAssembly exceptions are [WebAssembly.Exception](/en-US/docs/WebAssembly/JavaScript_interface/Exception) and [WebAssembly.Tag](/en-US/docs/WebAssembly/JavaScript_interface/Tag) ([Firefox bug 1759217](https://bugzil.la/1759217)).
### WebDriver conformance (Marionette)
- Added support for user prompts (e.g. `alert`) on Android ([Firefox bug 1708105](https://bugzil.la/1708105)).
## Changes for add-on developers
- The `color_scheme` and `content_color_scheme` properties are added to [theme](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/theme) manifest key and available in the {{WebExtAPIRef("theme")}} API. These properties enable a theme to override whether a light or dark color scheme is automatically applied to the chrome or content ([Firefox bug 1708105](https://bugzil.la/1708105)).
- You can now create a muted tab using {{WebExtAPIRef("tabs.create()")}} with the new `muted` property in the `createProperties` object ([Firefox bug 1372100](https://bugzil.la/1372100)).
- Support added for {{WebExtAPIRef("runtime.onSuspend")}} and {{WebExtAPIRef("runtime.onSuspendCanceled")}} improving support for event page features ([Firefox bug 1753850](https://bugzil.la/1753850)).
## Older versions
{{Firefox_for_developers(99)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/115/index.md | ---
title: Firefox 115 for developers
slug: Mozilla/Firefox/Releases/115
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 115 that affect developers. Firefox 115 was released on July 04, 2023.
## Changes for web developers
### HTML
- The [`modulepreload`](/en-US/docs/Web/HTML/Attributes/rel/modulepreload) keyword for the [`rel`](/en-US/docs/Web/HTML/Element/link#rel) attribute of the {{HTMLElement("link")}} element is now supported.
This allows early (and asynchronous) fetching of [module scripts](/en-US/docs/Web/JavaScript/Guide/Modules) and their dependencies in parallel, which are then stored in the document's module map ([Firefox bug 1425310](https://bugzil.la/1425310)).
### CSS
- The CSS {{cssxref("animation-composition")}} property is now supported by default. You can use this property to specify the composite operation to use when multiple animations affect the same property simultaneously. ([Firefox bug 1823862](https://bugzil.la/1823862)).
- The `supports-conditions` in the CSS {{cssxref("@import")}} [at-rule](/en-US/docs/Web/CSS/At-rule) `supports()` function is now supported by default. This feature allows stylesheets to be imported only if the specified feature is supported in the user's browser. ([Firefox bug 1830779](https://bugzil.la/1830779)).
### JavaScript
- The {{jsxref("Array.fromAsync()")}} static method is now supported.
The method asynchronously returns a new, shallow-copied `Array` instance from an [async iterable](/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#the_async_iterator_and_async_iterable_protocols), [iterable](/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#the_iterable_protocol), or [array-like](/en-US/docs/Web/JavaScript/Guide/Indexed_collections#working_with_array-like_objects) object ([Firefox bug 1795816](https://bugzil.la/1795816)).
- The `Array` and `TypedArray` methods [`Array.toReversed()`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toReversed), [`Array.toSorted()`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toSorted), [`Array.toSpliced()`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toSpliced), [`Array.with()`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/with), [`TypedArrays.toReversed()`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/toReversed), [`TypedArrays.toSorted()`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/toSorted), and [`TypedArrays.with()`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/with) are now supported.
These methods return a new array with elements that have been shallow copied (similarly named methods without the `to` prefix modify the array elements in place).
([Firefox bug 1811057](https://bugzil.la/1811057)).
### SVG
No notable changes.
### HTTP
- The [`Sec-Purpose`](/en-US/docs/Web/HTTP/Headers/Sec-Purpose) HTTP {{Glossary("Fetch metadata request header", "fetch metadata request header")}} is now included in requests to {{Glossary("Prefetch")}} resources.
This allows servers to provide any special handling that might be needed, such as adjusting the caching expiry for the request ([Firefox bug 1836328](https://bugzil.la/1836328)).
### APIs
- The [`Response.json()`](/en-US/docs/Web/API/Response/json_static) static method is now supported, making it easier to construct {{domxref("Response")}} objects for returning JSON data.
The method will be useful for [service workers](/en-US/docs/Web/API/Service_Worker_API) and any other code that needs to respond to browser requests with JSON data ([Firefox bug 1758943](https://bugzil.la/1758943)).
- The [`URL.canParse()`](/en-US/docs/Web/API/URL/canParse_static) static method can now be used to parse and validate an absolute URL, or a relative URL and base URL.
This provides a fast and easy way to check if URLs are valid, instead of constructing them within a `try...catch` block and handling exceptions.
([Firefox bug 1823354](https://bugzil.la/1823354)).
- The [`URLSearchParams.has()`](/en-US/docs/Web/API/URLSearchParams/has) and [`URLSearchParams.delete()`](/en-US/docs/Web/API/URLSearchParams/delete) methods now support the optional `value` argument.
This allows matching a search parameter on both the `name` and `value`, making it possible to work with query strings that contain multiple search parameters that have the same name.
([Firefox bug 1831587](https://bugzil.la/1831587)).
#### Removals
- The deprecated `mozPreservesPitch` alias of [HTMLMediaElement.preservesPitch](/en-US/docs/Web/API/HTMLMediaElement/preservesPitch) has been disabled by default, and may be fully removed in a future release ([Firefox bug 1831205](https://bugzil.la/1831205)).
### WebDriver conformance (WebDriver BiDi, Marionette)
#### WebDriver BiDi
- The payload now always includes stack traces for responses and events without capping it after the first 50 "throw" usages in a realm ([Firefox bug 1791715](https://bugzil.la/1791715)).
- When using `input.performActions`, any ongoing wheel transaction is now reset at the end of the command to not retain state and to not leak into following actions within the same tab ([Firefox bug 1821733](https://bugzil.la/1821733)).
- When using a `pointerMove` action with `input.performActions`, an invalid element origin now correctly raises a "no such error" failure ([Firefox bug 1832028](https://bugzil.la/1832028)).
- A race condition for the initial page load has been fixed that could appear when directly interacting with a newly opened tab or window ([Firefox bug 1832891](https://bugzil.la/1832891)).
#### Marionette
- Both the commands `WebDriver:GetComputedLabel` and `WebDriver:GetComputedRole` now correctly wait for the requested accessibility object for an element to exist if it just got inserted into the DOM ([Firefox bug 1828816](https://bugzil.la/1828816)).
- All instances of `window.setTimeout()` in our privileged code running in content processes now use a variant timer that is not affected by the throttling of the timers in case the given tab for automation is in the background.
## Changes for add-on developers
- To support its deprecation from Manifest V3 extensions, manifest key property [`browser_style`](/en-US/docs/Mozilla/Add-ons/WebExtensions/user_interface/Browser_styles) defaults to `false` in [`options_ui`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/options_ui) and [`sidebar_action`](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/sidebar_action) for Manifest V3 extensions ([Firefox bug 1830710](https://bugzil.la/1830710)). See [Manifest v3 migration](/en-US/docs/Mozilla/Add-ons/WebExtensions/user_interface/Browser_styles#manifest_v3_migration) for information about transitioning from `browser_style` in Manifest V3 extensions.
- The {{WebExtAPIRef("commands.onChanged")}} event, which enables web extensions to listen for changes to command shortcuts, has been added ([Firefox bug 1801531](https://bugzil.la/1801531)).
- Support has been added for {{WebExtAPIRef("storage.session")}}, which provides the ability to store data in memory for the duration of the browser session ([Firefox bug 18237131](https://bugzil.la/1823713)).
## Older versions
{{Firefox_for_developers(114)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/32/index.md | ---
title: Firefox 32 for developers
slug: Mozilla/Firefox/Releases/32
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
## Changes for Web developers
### Developer Tools
Highlights:
- [Web Audio Editor](https://firefox-source-docs.mozilla.org/devtools-user/web_audio_editor/index.html)
- _Code completion and inline documentation in Scratchpad]_
- [User agent styles in the Inspector's Rules view](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/index.html#rules-view)
- [Element picker button has moved](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/index.html#firefox-32-onwards-2)
- [Node dimensions added to the Inspector's infobar](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/index.html#firefox-32-onwards)
- [Full page screenshot button added](https://firefox-source-docs.mozilla.org/devtools-user/tools_toolbox/index.html#extra-tools)
- HiDPI images added to the tools
- Nodes that have `display:none` are shown differently in the Inspector
[All devtools bugs fixed between Firefox 31 and Firefox 32](https://bugzilla.mozilla.org/buglist.cgi?resolution=FIXED&classification=Client%20Software&chfieldto=2014-06-09&chfield=resolution&query_format=advanced&chfieldfrom=2014-04-28&chfieldvalue=FIXED&bug_status=RESOLVED&bug_status=VERIFIED&component=Developer%20Tools&component=Developer%20Tools%3A%203D%20View&component=Developer%20Tools%3A%20App%20Manager&component=Developer%20Tools%3A%20Canvas%20Debugger&component=Developer%20Tools%3A%20Console&component=Developer%20Tools%3A%20Debugger&component=Developer%20Tools%3A%20Framework&component=Developer%20Tools%3A%20Graphic%20Commandline%20and%20Toolbar&component=Developer%20Tools%3A%20Inspector&component=Developer%20Tools%3A%20Memory&component=Developer%20Tools%3A%20Netmonitor&component=Developer%20Tools%3A%20Object%20Inspector&component=Developer%20Tools%3A%20Profiler&component=Developer%20Tools%3A%20Responsive%20Mode&component=Developer%20Tools%3A%20Scratchpad&component=Developer%20Tools%3A%20Source%20Editor&component=Developer%20Tools%3A%20Style%20Editor&component=Developer%20Tools%3A%20User%20Stories&component=Developer%20Tools%3A%20WebGL%20Shader%20Editor&product=Firefox).
### CSS
- Enabled {{cssxref("mix-blend-mode")}} by default ([Firefox bug 952643](https://bugzil.la/952643)).
- Enabled `position:sticky` by default in release builds (only enabled on Nightly and Aurora before) ([Firefox bug 916315](https://bugzil.la/916315)).
- Implemented {{cssxref("box-decoration-break")}} and removed the non-standard `-moz-background-inline-policy` ([Firefox bug 613659](https://bugzil.la/613659)).
- Allowed {{cssxref("flex-grow")}} and {{cssxref("flex-shrink")}} to transition between zero and nonzero values, like 'flex-grow: 0.6'([Firefox bug 996945](https://bugzil.la/996945)).
### HTML
- Experimentally implemented, behind a pref, {{HTMLElement("img")}} [`srcset`](/en-US/docs/Web/HTML/Element/img#srcset) property, To activate it set `dom.image.srcset.enable` to `true` ([Firefox bug 870021](https://bugzil.la/870021)).
- [**id**](/en-US/docs/Web/HTML/Global_attributes/id) and [**class**](/en-US/docs/Web/HTML/Global_attributes/class) are now true [global attributes](/en-US/docs/Web/HTML/Global_attributes) and also apply to XML elements, in a namespace or not ([Firefox bug 741295](https://bugzil.la/741295)).
### JavaScript
- The following new ECMAScript 2015 built-in methods got implemented:
- {{jsxref("Array.from()")}} ([Firefox bug 904723](https://bugzil.la/904723)),
- {{jsxref("Array.prototype.copyWithin()")}} ([Firefox bug 934423](https://bugzil.la/934423)),
- {{jsxref("Number.isSafeInteger()")}} ([Firefox bug 1003764](https://bugzil.la/1003764)).
### Interfaces/APIs/DOM
- The {{domxref("Navigator.languages")}} property and {{domxref("Window.languagechange_event", "languagechange")}} event have been implemented ([Firefox bug 889335](https://bugzil.la/889335)).
- The {{domxref("Navigator.vibrate()")}} method behavior has been adapted to the latest specification: too long vibrations are now truncated ([Firefox bug 1014581](https://bugzil.la/1014581)).
- The {{domxref("KeyboardEvent.getModifierState()")}} and {{domxref("MouseEvent.getModifierState()")}} methods have been extended to support the `Accel` virtual modifier ([Firefox bug 1009388](https://bugzil.la/1009388)).
- The {{domxref("KeyboardEvent.code")}} property have been experimentally implemented: it is disabled on release build ([Firefox bug 865649](https://bugzil.la/865649)).
- Scoped selectors for {{domxref("Document.querySelector()")}} and {{domxref("Document.querySelectorAll()")}}, for example `querySelector(":scope > li")` have been implemented ([Firefox bug 528456](https://bugzil.la/528456)).
- The experimental implementation of the {{domxref("Document.timeline")}} interface, related to the [Web Animation API](https://drafts.fxtf.org/web-animations/), has been added ([Firefox bug 998246](https://bugzil.la/998246)). It is controlled by `layout.web-animations.api.enabled` preference, enabled only on Nightly and Aurora for the moment.
- The [Data Store API](/en-US/docs/Web/API/Data_Store_API) has been made available to [Web Workers](/en-US/docs/Web/API/Web_Workers_API/Using_web_workers) ([Firefox bug 949325](https://bugzil.la/949325)). It still is only activated for certified applications.
- The [ServiceWorker](/en-US/docs/Web/API/Service_Worker_API) {{domxref("InstallPhaseEvent")}} and {{domxref("InstallEvent")}} interfaces have been implemented ([Firefox bug 967264](https://bugzil.la/967264)).
- The [MSISDN Verification API](/en-US/docs/Web/API/MSISDN_Verification_API), only activated for privileged apps, has been added ([Firefox bug 988469](https://bugzil.la/988469)).
- The [Gamepad API](/en-US/docs/Web/API/Gamepad_API) is now supported on Firefox for Android ([Firefox bug 852935](https://bugzil.la/852935)).
- To match the spec and the evolution of the CSS syntax, minor changes have been done to {{domxref("CSS.escape_static", "CSS.escape()")}}. The identifier now can begins with `'--'` and the second dash must not be escaped. Also vendor identifier are no more escaped. ([Firefox bug 1008719](https://bugzil.la/1008719))
- To complete our Hit Regions implementation, `MouseEvent.region` has been implemented ([Firefox bug 979692](https://bugzil.la/979692)).
- The {{domxref("CanvasRenderingContext2D.drawFocusIfNeeded()")}} method is now enabled by default ([Firefox bug 1004579](https://bugzil.la/1004579)).
- The {{domxref("Navigator.doNotTrack")}} properties now returns `'1'` or `'0'`, reflecting the HTTP value, instead of `'yes'` or `'no'` ([Firefox bug 887703](https://bugzil.la/887703)).
- [XMLHttpRequest.responseURL](/en-US/docs/Web/API/XMLHttpRequest/responseURL) was implemented ([Firefox bug 998076](https://bugzil.la/998076))..
### MathML
- Add support for the {{MathMLElement("menclose")}} notation `phasorangle`.
### SVG
_No change._
### WebRTC
- New constraints for [WebRTC](/en-US/docs/Glossary/WebRTC)'s {{domxref("NavigatorUserMedia.getUserMedia", "getUserMedia()")}}, `width`, `height`, and `framerate`, have been added, to limit stream dimensions and frame rate ([Firefox bug 907352](https://bugzil.la/907352)):
```js
{
mandatory: {
width: { min: 640 },
height: { min: 480 },
},
optional: [
{ width: 650 },
{ width: { min: 650 }},
{ frameRate: 60 },
{ width: { max: 800 }},
]
}
```
- WebRTC methods which previously used callback functions as input parameters are now also available using JavaScript [promises](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise).
### Audio/Video
_No change._
## Security
- [Privileged code now gets Xray vision for JavaScript `Object` and `Array` instances](https://firefox-source-docs.mozilla.org/dom/scriptSecurity/xray_vision.html#xray-semantics-for-object-and-array).
## Changes for add-on and Mozilla developers
Xray vision is now applied to JavaScript objects that are not themselves DOM objects: [Xrays for JavaScript objects](https://firefox-source-docs.mozilla.org/dom/scriptSecurity/xray_vision.html#xrays-for-javascript-objects).
A `getDataDirectory()` method has been added to [`Addon`](/en-US/docs/Mozilla/Add-ons/Add-on_Manager/Addon) instances. This method returns the preferred location, within the current profile, for add-ons to store data.
### Add-on SDK
#### Highlights
- Added [`exclude`](/en-US/docs/Mozilla/Add-ons/SDK/High-Level_APIs/page-mod#pagemod%28options%29) option to `PageMod`.
- Added [`anonymous`](/en-US/docs/Mozilla/Add-ons/SDK/High-Level_APIs/request#request%28options%29) option to `Request`.
- [Add-on Debugger](/en-US/docs/Mozilla/Add-ons/Add-on_Debugger) now includes a Console and a Scratchpad.
#### Details
[GitHub commits made between Firefox 31 and Firefox 32](https://github.com/mozilla/addon-sdk/compare/firefox31...firefox32). This will not include any uplifts made after this release entered Aurora.
[Bugs fixed between Firefox 31 and Firefox 32](https://bugzilla.mozilla.org/buglist.cgi?resolution=FIXED&chfieldto=2014-06-09&chfield=resolution&query_format=advanced&chfieldfrom=2014-04-28&chfieldvalue=FIXED&bug_status=RESOLVED&bug_status=VERIFIED&bug_status=CLOSED&product=Add-on%20SDK&list_id=10493962). This will not include any uplifts made after this release entered Aurora.
### XPCOM
- The `nsIUDPSocket` interface now provides multicast support through the addition of the new `nsIUDPSocket.multicastLoopback`, `nsIUDPSocket.multicastInterface`, and `nsIUDPSocket.multicastInterfaceAddr` attributes, as well as the `nsIUDPSocket.joinMulticast()` and `nsIUDPSocket.leaveMulticast()` methods.
### Older versions
{{Firefox_for_developers('31')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/80/index.md | ---
title: Firefox 80 for developers
slug: Mozilla/Firefox/Releases/80
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 80 that will affect developers. Firefox 80 was released on August 25, 2020.
## Changes for web developers
### Developer Tools
- You can now block and unblock network requests using the `:block` and `:unblock` [helper commands](https://firefox-source-docs.mozilla.org/devtools-user/web_console/helpers/index.html) in the Web Console ([Firefox bug 1546394](https://bugzil.la/1546394)).
- When [adding a class](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_css/index.html#viewing-and-changing-classes-on-an-element) to an element in the Page Inspector's Rules pane, existing classes are suggested with autocomplete (Refer to [Firefox bug 1492797](https://bugzil.la/1492797)).
- When the Debugger [breaks on an exception](https://firefox-source-docs.mozilla.org/devtools-user/debugger/how_to/breaking_on_exceptions/index.html), the tooltip in the source pane now shows a disclosure triangle that reveals a stack trace ([Firefox bug 1643633](https://bugzil.la/1643633)).
- In the [Network Monitor request list](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_list/index.html#network-request-columns), a turtle icon is shown for "slow" requests that exceed a configurable threshold for the waiting time ([Firefox bug 1648373](https://bugzil.la/1648373)).
### HTML
_No changes._
### CSS
- The standard, unprefixed {{CSSxRef("appearance", "appearance")}} property is now supported; existing `-moz-appearance` and `-webkit-appearance` are now aliases of the unprefixed property ([Firefox bug 1620467](https://bugzil.la/1620467)).
### JavaScript
- The ECMAScript 2021 `export * as namespace` syntax for the [`export`](/en-US/docs/Web/JavaScript/Reference/Statements/export) statement is now supported ([Firefox bug 1496852](https://bugzil.la/1496852)).
### HTTP
- Previously, when the [fullscreen](/en-US/docs/Web/HTTP/Headers/Permissions-Policy/fullscreen) directive was applied to an [`<iframe>`](/en-US/docs/Web/HTML/Element/iframe) (i.e. via the `allow` attribute), it didn't work unless the `allowfullscreen` attribute was also present This has now been fixed ([Firefox bug 1608358](https://bugzil.la/1608358)).
### APIs
#### DOM
- Web Animations API compositing operations are now enabled — see [`KeyframeEffect.composite`](/en-US/docs/Web/API/KeyframeEffect/composite) and [`KeyframeEffect.iterationComposite`](/en-US/docs/Web/API/KeyframeEffect/iterationComposite) ([Firefox bug 1652676](https://bugzil.la/1652676)).
#### Removals
- The `outerHeight` and `outerWidth` features of [`Window.open()`](/en-US/docs/Web/API/Window/open) are no longer exposed to web content ([Firefox bug 1623826](https://bugzil.la/1623826)).
### WebAssembly
- Atomic operations are now allowed on non-shared memories ([Firefox bug 1619196](https://bugzil.la/1619196)).
### WebDriver conformance (Marionette)
- Using `WebDriver:NewWindow` to open a new tab no longer returns too early when running tests in headless mode ([Firefox bug 1653281](https://bugzil.la/1653281)).
- We removed the `name` argument for `WebDriver:SwitchToWindow` — it is not supported for W3C-compatible mode, and shouldn't be used anymore ([Firefox bug 1588424](https://bugzil.la/1588424)).
- We've started to add Fission support for the following commands: `WebDriver:FindElement`, `WebDriver:FindElements`, `WebDriver:GetElementAttribute`, `WebDriver:GetElementProperty`.
- **Known issue**: Opening a new tab by using `WebDriver:NewWindow`, or via an arbitrary script that calls `window.open()`, now automatically switches to that new window ([Firefox bug 1661495](https://bugzil.la/1661495)).
## Changes for add-on developers
_No changes._
## Older versions
{{Firefox_for_developers(79)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/50/index.md | ---
title: Firefox 50 for developers
slug: Mozilla/Firefox/Releases/50
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
[To test the latest developer features of Firefox, install Firefox Developer Edition](https://www.mozilla.org/firefox/developer/)Firefox 50 was released on November 15, 2016. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.
## Changes for Web developers
### HTML
- The default style of {{HTMLElement("bdo")}} now sets {{cssxref("unicode-bidi")}} with the `isolate-override` value ([Firefox bug 1249497](https://bugzil.la/1249497)).
- Setting the {{HTMLElement("track")}} element's [`src`](/en-US/docs/Web/HTML/Element/track#src) attribute now works correctly ([Firefox bug 1281418](https://bugzil.la/1281418)).
- The `referrerpolicy` attribute on {{HTMLElement("area")}}, {{HTMLElement("a")}}, {{HTMLElement("img")}}, {{HTMLElement("iframe")}} and {{HTMLElement("link")}} elements is now available by default ([Firefox bug 1223838](https://bugzil.la/1223838), [Firefox bug 1264165](https://bugzil.la/1264165)).
### CSS
- Border-radiused corners with dashed and dotted styles are now rendered with the specified style instead of a solid style ([Firefox bug 382721](https://bugzil.la/382721)).
- The non-standard `:-moz-full-screen-ancestor` pseudo-class selector has been removed ([Firefox bug 1199529](https://bugzil.la/1199529)).
- The {{cssxref("box-sizing")}}`: padding-box` has been removed, since it's no longer a part of the spec and Firefox was the only major browser implementing it ([Firefox bug 1166728](https://bugzil.la/1166728)).
- The three values `isolate`, `isolate-override`, and `plaintext` of the {{cssxref("unicode-bidi")}} property have been unprefixed ([Firefox bug 1141895](https://bugzil.la/1141895)).
- In quirks mode, the bullet of a list item now inherits the size of the list, like in standards mode ([Firefox bug 648331](https://bugzil.la/648331)).
- The {{cssxref(":in-range")}} and {{cssxref(":out-of-range")}} pseudo-classes have changed behavior to not match disabled or read-only inputs ([Firefox bug 1264157](https://bugzil.la/1264157)).
- The {{cssxref(":any-link")}} pseudo-class is now unprefixed ([Firefox bug 843579](https://bugzil.la/843579)).
- The `space` value for {{cssxref("border-image-repeat")}} has been implemented ([Firefox bug 720531](https://bugzil.la/720531)).
### JavaScript
- The ES2015 {{jsxref("Symbol.hasInstance")}} property has been implemented ([Firefox bug 1054906](https://bugzil.la/1054906)).
- The ES2017 {{jsxref("Object.getOwnPropertyDescriptors()")}} method has been implemented ([Firefox bug 1245024](https://bugzil.la/1245024)).
- The behavior of \W in {{jsxref("RegExp")}} with unicode and ignoreCase flags is changed to match recent draft spec. Now it doesn't match to K, S, k, s, and KELVIN SIGN (U+212A), and LATIN SMALL LETTER LONG S (U+017F) ([Firefox bug 1281739](https://bugzil.la/1281739)).
### Developer Tools
- [The Web Console now understands source maps.](https://firefox-source-docs.mozilla.org/devtools-user/web_console/console_messages/index.html#source-maps)
- [The Storage Inspector now lets you delete individual items from IndexedDB object stores.](https://firefox-source-docs.mozilla.org/devtools-user/storage_inspector/index.html#indexeddb)
- [The Memory tool is enabled by default.](https://firefox-source-docs.mozilla.org/devtools-user/memory/index.html)
- [The Box model view is moved into the Computed view.](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/ui_tour/index.html#computed-view)
- [The Web Console now displays stack traces for XHR or Fetch() network requests.](https://firefox-source-docs.mozilla.org/devtools-user/web_console/console_messages/index.html#viewing-network-request-details)
[All devtools bugs fixed between Firefox 49 and Firefox 50](https://bugzilla.mozilla.org/buglist.cgi?list_id=13263766&chfield=resolution&chfieldfrom=2016-06-06&chfieldvalue=FIXED&resolution=FIXED&classification=Client%20Software&chfieldto=2016-08-01&query_format=advanced&bug_status=RESOLVED&bug_status=VERIFIED&component=Developer%20Tools&component=Developer%20Tools%3A%20about%3Adebugging&component=Developer%20Tools%3A%20Animation%20Inspector&component=Developer%20Tools%3A%20Canvas%20Debugger&component=Developer%20Tools%3A%20Computed%20Styles%20Inspector&component=Developer%20Tools%3A%20Console&component=Developer%20Tools%3A%20CSS%20Rules%20Inspector&component=Developer%20Tools%3A%20Debugger&component=Developer%20Tools%3A%20DOM&component=Developer%20Tools%3A%20Font%20Inspector&component=Developer%20Tools%3A%20Framework&component=Developer%20Tools%3A%20Graphic%20Commandline%20and%20Toolbar&component=Developer%20Tools%3A%20Inspector&component=Developer%20Tools%3A%20JSON%20Viewer&component=Developer%20Tools%3A%20Memory&component=Developer%20Tools%3A%20Netmonitor&component=Developer%20Tools%3A%20Object%20Inspector&component=Developer%20Tools%3A%20Performance%20Tools%20%28Profiler%2FTimeline%29&component=Developer%20Tools%3A%20Responsive%20Design%20Mode&component=Developer%20Tools%3A%20Scratchpad&component=Developer%20Tools%3A%20Shared%20Components&component=Developer%20Tools%3A%20Source%20Editor&component=Developer%20Tools%3A%20Storage%20Inspector&component=Developer%20Tools%3A%20Style%20Editor&component=Developer%20Tools%3A%20User%20Stories&component=Developer%20Tools%3A%20Web%20Audio%20Editor&component=Developer%20Tools%3A%20WebGL%20Shader%20Editor&component=Developer%20Tools%3A%20WebIDE&product=Firefox).
### HTTP
- The experimental (and deprecated) [SPDY](https://en.wikipedia.org/wiki/SPDY) 3.1 is now disabled by default [Firefox bug 1287132](https://bugzil.la/1287132).
- Support for {{HTTPHeader("X-Content-Type-Options")}} has been added ([Firefox bug 471020](https://bugzil.la/471020)).
- The cookie prefixes `__Host-` and `__Secure-` have been implemented. See {{HTTPHeader("Set-Cookie")}} and [Firefox bug 1283368](https://bugzil.la/1283368).
- The {{HTTPHeader("Referrer-Policy")}} header has been implemented [Firefox bug 1264164](https://bugzil.la/1264164).
### Security
- The [`ping`](/en-US/docs/Web/HTML/Element/a#ping) attribute of {{htmlelement("a")}} element now abides by the [`connect-src`](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy#connect-src) [CSP 1.1 policy directive](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy) ([Firefox bug 1100181](https://bugzil.la/1100181)).
- Support for the [`sandbox`](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy#sandbox) [CSP](/en-US/docs/Web/HTTP/CSP) directive has been added ([Firefox bug 671389](https://bugzil.la/671389)).
- It's now possible to set a [content security policy for workers](/en-US/docs/Web/API/Web_Workers_API/Using_web_workers#content_security_policy) ([Firefox bug 959388](https://bugzil.la/959388)).
- The {{domxref("Navigator.sendBeacon()")}} method no longer throws an exception if the beacon data couldn't be sent due to a [Content Security Policy](/en-US/docs/Web/HTTP/CSP) restriction; instead, it returns `false` as expected ([Firefox bug 1234813](https://bugzil.la/1234813)).
- Support for RC4 encryption was deprecated in Firefox 36 and disabled by default in Firefox 44. The one-year grace period has ended, so Firefox 50 removes all support for RC4 (Google Chrome removed support for RC4 in August 2016). From now on, any time Firefox encounters RC4 encryption, it will report an `SSL_ERROR_NO_CYPHER_OVERLAP` error.
### Networking
- When an error has happened during an asynchronous {{domxref("XMLHttpRequest")}}, the {{domxref("XMLHttpRequest.getAllResponseHeaders()")}} method now returns an empty string ([Firefox bug 1286744](https://bugzil.la/1286744)).
- Instead of returning a `NetworkError`, asynchronous {{domxref("XMLHttpRequest")}} that fails for CORS or other network constraints now raises an {{domxref("XMLHttpRequest/error_event", "error")}} that can be caught like any other error ([Firefox bug 709991](https://bugzil.la/709991)).
- {{domxref("XMLHttpRequest.getResponseHeader()")}} and {{domxref("XMLHttpRequest.getAllResponseHeaders()")}} now also return empty headers by default. This can be controlled via the preference `network.http.keep_empty_response_headers_as_empty_string` ([Firefox bug 918721](https://bugzil.la/918721)).
- The `only-if-cached` option has been added to [`Request.cache`](/en-US/docs/Web/API/Request/cache) ([Firefox bug 1272436](https://bugzil.la/1272436)).
### DOM
- The `once` option for {{domxref("EventTarget.addEventListener()")}} is now supported ([Firefox bug 1287706](https://bugzil.la/1287706)).
- The interface {{domxref("NodeList")}} are now iterable and the methods {{domxref("NodeList.forEach()", "forEach()")}}, {{domxref("NodeList.values()", "values()")}}, {{domxref("NodeList.entries()")}} and {{domxref("NodeList.keys()")}} are now available ([Firefox bug 1290636](https://bugzil.la/1290636)).
- The interface {{domxref("DOMTokenList")}} are now iterable and the methods {{domxref("DOMTokenList.forEach()", "forEach()")}}, {{domxref("DOMTokenList.values()", "values()")}}, {{domxref("DOMTokenList.entries()")}} and {{domxref("DOMTokenList.keys()")}} are now available ([Firefox bug 1290636](https://bugzil.la/1290636)).
- The methods {{domxref("Document.createElement()")}} and {{domxref("Document.createElementNS()")}} now have an optional `options` parameter for creating [custom elements](/en-US/docs/Web/API/Web_components/Using_custom_elements) ([Firefox bug 1276579](https://bugzil.la/1276579)).
### SVG
- The `allowReorder` attribute has been dropped and the behavior it was setting is now the default for SVG {{SVGElement("switch")}} elements ([Firefox bug 1279690](https://bugzil.la/1279690)).
- The `defer` keyword for the {{SVGAttr("preserveAspectRatio")}} attribute on SVG {{SVGElement("image")}} elements has been removed to follow the latest SVG2 specification ([Firefox bug 1280425](https://bugzil.la/1280425)).
### Drag and Drop API
- The {{domxref("DataTransfer.items")}} property has been implemented, allowing access to multiple items being dragged and dropped using the HTML Drag and Drop API. To allow this, the {{domxref("DataTransferItem")}} and {{domxref("DataTransferItemList")}} interfaces are now supported as well ([Firefox bug 906420](https://bugzil.la/906420)). This is enabled by default.
- The old, obsolete Firefox specific drag and drop API events `dragdrop` and `draggesture` are no longer supported. Be sure to update any code still using them to use the [HTML drag and drop API](/en-US/docs/Web/API/HTML_Drag_and_Drop_API) ([Firefox bug 1162050](https://bugzil.la/1162050).
### Pointer Lock API
- The [Pointer Lock API](/en-US/docs/Web/API/Pointer_Lock_API) is now unprefixed ([Firefox bug 991899](https://bugzil.la/991899)).
- Before Firefox 50, [`requestPointerLock()`](/en-US/docs/Web/API/Element/requestPointerLock) asked for permission using a doorhanger, and pointer lock would not be enabled until the user granted permission. From Firefox 50, pointer lock is like the [fullscreen API](/en-US/docs/Web/API/Fullscreen_API): it's granted immediately, but a notification is displayed explaining to the user how to exit ([Firefox bug 1273351](https://bugzil.la/1273351)).
### IndexedDB
- A {{domxref("IDBDatabase/close_event", "close")}} event is now sent to the {{domxref("IDBDatabase")}} object when the corresponding database is unexpectedly closed ([Firefox bug 1151017](https://bugzil.la/1151017)).
### Service Workers
- The {{domxref("WindowClient.navigate()")}} method has been implemented. This method lets you open a specified URL into a client window which is being controlled by the service worker ([Firefox bug 1218148](https://bugzil.la/1218148)).
### WebGL
- The {{domxref("EXT_shader_texture_lod")}} WebGL extension has been implemented ([Firefox bug 1111689](https://bugzil.la/1111689)).
- The texImage methods have been updated for [WebGL 2](/en-US/docs/Web/API/WebGL2RenderingContext) to implement PBOs (`PIXEL_UNPACK_BUFFER`) ([Firefox bug 1280499](https://bugzil.la/1280499)).
### WebRTC
- Adding a track to a {{domxref("MediaStream")}} now generates the {{domxref("MediaStream/addtrack_event", "addtrack")}} event as described in the specification. The event is of type {{domxref("MediaStreamTrackEvent")}} and is fired on the stream to which the track was added. You can use either {{domxref("EventTarget.addEventListener", "MediaStream.addEventListener('addtrack', ...)")}} or the `onaddtrack` property to handle `"addtrack"` events.
- The {{domxref("MediaStreamTrack")}} interface now supports the {{domxref("MediaStreamTrack.ended_event", "ended")}} event and its event handler.
- Firefox now supports the {{domxref("MediaStreamTrack.readyState")}} property, which indicates whether the track is live or permanently ended.
- The {{domxref("MediaStreamTrack")}} methods {{domxref("MediaStreamTrack.getConstraints", "getConstraints()")}} and {{domxref("MediaStreamTrack.getSettings", "getSettings()")}} have been implemented; these let you get the most recently applied set of customized property constraints and the actual values of all of the track's constrainable properties, respectively. The accompanying data types have been documented as well.
- The `RTCDataChannel.stream` property has been removed. This was replaced with {{domxref("RTCDataChannel.id")}} in [Firefox 24](/en-US/docs/Mozilla/Firefox/Releases/24), but was supported for backward compatibility. Please be sure to update your code to use the `id` property if you haven't done so yet.
### Web Audio API
- The {{domxref("PannerNode")}} interface now supports the 3D Cartesian space properties for the position ({{domxref("PannerNode.positionX")}}, {{domxref("PannerNode.positionY")}}, and {{domxref("PannerNode.positionZ")}}) and directionality ({{domxref("PannerNode.orientationX")}}, {{domxref("PannerNode.orientationY")}}, {{domxref("PannerNode.orientationZ")}}) of an audio source.
- The interface {{domxref("IIRFilterNode")}}, which implements a general [infinite impulse response](https://en.wikipedia.org/wiki/Infinite_impulse_response) (IIR) filter, has been implemented.
- Throttling in background tabs of timers created by {{domxref("setInterval()")}} and {{domxref("setTimeout()")}} no longer occurs if a [Web Audio API](/en-US/docs/Web/API/Web_Audio_API) {{domxref("AudioContext")}} is actively playing sound. This should help prevent issues with timing-sensitive audio playback (such as music players generating individual notes using timers) in the background ([Firefox bug 1181073](https://bugzil.la/1181073)).
### Audio/Video
- The `AlignSetting` enum (representing possible values for {{domxref("VTTCue.align")}}) incorrectly previously included the value `"middle"` instead of `"center"`. This has been corrected ([Firefox bug 1276130](https://bugzil.la/1276130)).
- The non-standard and experimental method {{domxref("HTMLMediaElement.seekToNextFrame()")}} now seeks to the next frame in the media asynchronously, rather than synchronously, and returns a {{jsxref("Promise")}} which resolves once the seek is complete.
- The implementation of {{domxref("HTMLTrackElement")}} has been corrected to allow {{HTMLElement("track")}} elements to load resources even if not in a document ([Firefox bug 871747](https://bugzil.la/871747)).
### Battery API
- The `Navigator.battery` property, which has been deprecated since Firefox 43, is now obsolete and has been removed. Use the {{domxref("navigator.getBattery()")}} method instead to get a battery {{jsxref("Promise")}}, which will resolve when the {{domxref("BatteryManager")}} is available for use; the {{domxref("BatteryManager")}} is passed into the fulfillment handler for the promise ([Firefox bug 12593355](https://bugzil.la/12593355)).
### Files and directories
- A subset of the [File and Directory Entries API](/en-US/docs/Web/API/File_and_Directory_Entries_API) has been implemented, to improve compatibility with sites that were previously only compatible with Google Chrome ([Firefox bug 1265767](https://bugzil.la/1265767)).
- The asynchronous API interfaces have been implemented, with the caveat that only reading of files is supported; for example, the {{domxref("FileSystemFileEntry.createWriter()")}} method is a no-op.
- These interfaces have been implemented:
- {{domxref("FileSystem")}}
- {{domxref("FileSystemEntry")}} (properties only; the methods have not been implemented)
- {{domxref("FileSystemFileEntry")}} (except for {{domxref("FileSystemFileEntry.createWriter", "createWriter()")}})
- {{domxref("FileSystemDirectoryEntry")}} (except for {{domxref("FileSystemDirectoryEntry.removeRecursively", "removeRecursively()")}})
- {{domxref("FileSystemDirectoryReader")}}
- {{domxref("HTMLInputElement.webkitdirectory")}} as well as the [`webkitdirectory`](/en-US/docs/Web/HTML/Element/input#webkitdirectory) attribute of the {{HTMLElement("input")}} element have been implemented; this lets you configure a file input to accept directories instead of files ([Firefox bug 1258489](https://bugzil.la/1258489)).
- {{domxref("HTMLInputElement.webkitEntries")}} has been implemented; this returns an array of {{domxref("FileSystemEntry")}}-based objects representing the selected items.
- {{domxref("File.webkitRelativePath")}} has been implemented; this contains the path of the file relative to the root of the containing {{domxref("FileSystemDirectoryEntry")}} that was among the items in the list returned by {{domxref("HTMLInputElement.webkitGetEntries()")}}.
- See [File and Directory Entries API support in Firefox](/en-US/docs/Web/API/File_and_Directory_Entries_API/Firefox_support) for details about what we do and do not support in this API.
- These APIs are now enabled by default; some were previously available but only behind a preference ([Firefox bug 1288683](https://bugzil.la/1288683)).
- We've implemented {{domxref("DataTransferItem.webkitGetAsEntry()")}} as part of the [File and Directory Entries API](/en-US/docs/Web/API/File_and_Directory_Entries_API); this lets you obtain a {{domxref("FileSystemEntry")}} representing a dropped file ([Firefox bug 1289255](https://bugzil.la/1289255)). This is enabled by default.
- The `HTMLInputElement.directory` property, part of the [Directory Upload API](https://wicg.github.io/directory-upload/proposal.html) proposal, has been renamed to `allowdirs` ([Firefox bug 1288681](https://bugzil.la/1288681)). This property is hidden behind a preference.
## Older versions
{{Firefox_for_developers(49)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/17/index.md | ---
title: Firefox 17 for developers
slug: Mozilla/Firefox/Releases/17
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
Firefox 17 shipped on November 20, 2012. This article lists key changes that are useful for not only web developers, but also Firefox and Gecko developers as well as add-on developers.
## Changes for Web developers
### HTML
- Support for the [`sandbox`](/en-US/docs/Web/HTML/Element/iframe#sandbox) attribute on the {{HTMLElement("iframe")}} element has been added. ([Firefox bug 341604](https://bugzil.la/341604))
### CSS
- Support for {{cssxref("@supports")}} at-rule defined in [CSS Conditional Rules Module Level 3](https://drafts.csswg.org/css-conditional-3/) has been landed. It is disabled by default. Developers can try it by setting `layout.css.supports-rule.enabled` to true ([bug 649740](https://bugzil.la/649740)).
- Support for the CSS Selectors Level 4 pseudo-class {{cssxref(":dir", ":dir()")}} allowing selection of elements based on their directionality has landed. ([bug 562169](https://bugzil.la/562169))
- Support for the newly specified `isolate-override` value of the CSS {{cssxref("unicode-bidi")}} value has landed ([Firefox bug 774335](https://bugzil.la/774335))
- Our prefixed implementation of {{cssxref("box-sizing")}} now takes into account {{cssxref("min-height")}} and {{cssxref("max-height")}}. One step closer to its unprefixing ([Firefox bug 308801](https://bugzil.la/308801))
### DOM/APIs
- Support for {{domxref("CSSSupportsRule")}} interface defined in [CSS3 Conditional Rules specification](https://drafts.csswg.org/css-conditional-3/) has been landed ([Firefox bug 649740](https://bugzil.la/649740))
- Support for {{domxref("WheelEvent")}} object and `wheel` event have been landed ([Firefox bug 719320](https://bugzil.la/719320)).
- Support DOM Meta key on Linux again ([Firefox bug 751749](https://bugzil.la/751749)).
- On {{domxref("HTMLMediaElement")}}, a new method, `mozGetMetadata`, that returns a JavaScript object whose properties represent metadata from the playing media resource as {key: value} pairs ([Firefox bug 763010](https://bugzil.la/763010)).
- Support for {{domxref("Range.intersectsNode")}} has been added again; it has been removed in Gecko 1.9 ([Firefox bug 579638](https://bugzil.la/579638).
- {{domxref("Range.compareBoundaryPoints()")}} now throws a {{domxref("DOMException")}} with the `NOT_SUPPORTED_ERR` value when the comparison method is invalid ([Firefox bug 714279](https://bugzil.la/714279)) .
- {{domxref("Event.initEvent()")}} has been adapted to the spec: it doesn't throw anymore if called after the dispatch of the event, it is only a no-op ([Firefox bug 768310](https://bugzil.la/768310)).
- The non-standard {{domxref("XMLHttpRequest", "XMLHttpRequest.onuploadrequest")}} property has been removed ([Firefox bug 761278](https://bugzil.la/761278)).
- The method {{domxref("XMLHttpRequest.getAllResponseHeaders()")}} now separates them with a CRLF (instead of a LF), as requested by the spec ([Firefox bug 730925](https://bugzil.la/730925)).
### JavaScript
- [`String`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/String) object now offers Harmony [`startsWith`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith), [`endsWith`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith), and [`contains`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes) methods ([Firefox bug 772733](https://bugzil.la/772733)).
- The String methods [link](/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/link) and [anchor](/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/anchor) now escape the `'"'` (quotation mark) ([Firefox bug 352437](https://bugzil.la/352437)).
- Experimental support for strawman `ParallelArray` object has been implemented ([Firefox bug 778559](https://bugzil.la/778559)).
- Support to iterate [`Map`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map)/[`Set`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set) ([Firefox bug 725909](https://bugzil.la/725909)).
- Disabled EcmaScript for XML (E4X), an abandoned JavaScript extension, for web content by default ([Firefox bug 778851](https://bugzil.la/778851)).
- `__exposedProps__` must now be set for Chrome JavaScript objects exposed to content. Attempts to access Chrome objects from content without `__exposedProps__` set will fail silently ([Firefox bug 553102](https://bugzil.la/553102)).
- [`for...of`](/en-US/docs/Web/JavaScript/Reference/Statements/for...of) loops now work in terms of `.iterator()` and `.next()` ([Firefox bug 725907](https://bugzil.la/725907)).
### WebGL
- The {{domxref("EXT_texture_filter_anisotropic")}} WebGL extension has been unprefixed. Using `"MOZ_EXT_texture_filter_anisotropic"` will present a warning from now on. The prefixed name is going to be removed in a future release ([Firefox bug 776001](https://bugzil.la/776001)).
### SVG
_No change._
### MathML
- The parsing of the `align` attribute on {{MathMLElement("mtable")}} elements has been updated to treat optional spaces more correctly.
### XUL
- XUL `key` element supports "os" modifier which is Win key (Super or Hyper key) ([Firefox bug 778732](https://bugzil.la/778732)).
### Network
- Removed the non-standard feature `XMLHttpRequest.onuploadprogress` which was deprecated in Firefox 14.
_No change._
### Developer tools
- Change JSTerm's $ helper function from getElementById to querySelector() ([Firefox bug 751749](https://bugzil.la/751749)).
### User Agent
The Gecko part of the user agent string changed. The build date (which hadn't been updated since 2010) was removed, and the Gecko version number was put in its place instead. So `Gecko/20100101` -> `Gecko/17.0`. This may affect you if you are doing user agent sniffing.
## Changes for add-on and Mozilla developers
### Interface changes
- `nsIInputStream`
- : The `available()` method returns 64-bit length instead of 32-bit ([Firefox bug 215450](https://bugzil.la/215450)).
- `nsIDOMWindowUtils`
- : The `sendMouseScrollEvent()` method has been replaced with `sendWheelEvent()` ([Firefox bug 719320](https://bugzil.la/719320)).
- `nsIFilePicker`
- : The `open()` method, to open the file dialog asynchronously, has been added and the `show()` method has been deprecated ([Firefox bug 731307](https://bugzil.la/731307)).
- `nsIScriptSecurityManager`
- : The `checkLoadURIStr()` and `checkLoadURI()` methods have been removed ([Firefox bug 327244](https://bugzil.la/327244)).
- `nsIRefreshURI`
- : The `setupRefreshURIFromHeader()` method has a `principal` parameter added ([Firefox bug 327244](https://bugzil.la/327244)).
#### New interfaces
None.
#### Removed interfaces
None removed.
## See also
- [Firefox 17 Release Notes](https://website-archive.mozilla.org/www.mozilla.org/firefox_releasenotes/en-us/firefox/17.0/releasenotes/)
- [Aurora 17 is out, bringing better security and support for new standards](https://hacks.mozilla.org/2012/08/aurora-17-is-out/) (Mozilla Hacks)
- [Add-on Compatibility for Firefox 17](https://blog.mozilla.org/addons/2012/11/08/compatibility-for-firefox-17/) (Add-ons Blog)
### Older versions
{{Firefox_for_developers('16')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/96/index.md | ---
title: Firefox 96 for developers
slug: Mozilla/Firefox/Releases/96
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 96 that affect developers. Firefox 96 was released on January 11, 2022.
## Changes for web developers
### HTML
No notable changes
### CSS
- The [`hwb()`](/en-US/docs/Web/CSS/color_value/hwb) function for use as a [CSS color value](/en-US/docs/Web/CSS/color_value) has been implemented. The `hwb()` functional notation expresses a given color according to its hue, whiteness, and blackness. An optional alpha component represents the color's transparency. ([Firefox bug 1352755](https://bugzil.la/1352755)).
- Firefox now provides support for the {{CSSxRef("color-scheme")}} property. This allows an element to indicate which color schemes it can comfortably be rendered in. Common options include "light" and "dark", or "day mode" and "night mode". ([Firefox bug 1576289](https://bugzil.la/1576289)).
- The {{CSSxRef("counter-reset")}} property now supports the `reversed()` function for creating _reversed_ [CSS counters](/en-US/docs/Web/CSS/CSS_counter_styles/Using_CSS_counters), which are intended for numbering elements in descending order.
This can be used with the `list-item` counter to automatically number ordered lists in reverse order, starting from the number of elements in the list
(`list-item` is a counter that is automatically applied for ordered lists, such as those created using {{HTMLElement("ol")}}).
Firefox uses this feature internally to support the `<ol>` [`reversed` attribute](/en-US/docs/Web/HTML/Element/ol#reversed).
([Firefox bug 1706346](https://bugzil.la/1706346)).
### JavaScript
No notable changes.
### HTTP
No notable changes.
### APIs
- {{domxref("navigator.canShare()")}} is now supported on Android, allowing code to check whether {{domxref("navigator.share()")}} will succeed for particular targets.
The feature is behind a preference on desktop operating systems.
([Firefox bug 1666203](https://bugzil.la/1666203)).
- The [Web Locks API](/en-US/docs/Web/API/Web_Locks_API) is enabled by default, allowing web apps running in multiple tabs or workers to coordinate the use of resources. ([Firefox bug 1740044](https://bugzil.la/1740044)).
#### Canvas
- Image encoder support has been added for the [WebP](/en-US/docs/Web/Media/Formats/Image_types#webp_image) image format.
This allows canvas elements to export their content as webp data when using the methods: {{domxref("HTMLCanvasElement.toDataURL()")}}, {{domxref("HTMLCanvasElement.toBlob()")}}, and {{domxref("OffscreenCanvas.convertToBlob", "OffscreenCanvas.toBlob")}}.
([Firefox bug 1511670](https://bugzil.la/1511670)).
#### DOM
- The {{domxref("IntersectionObserver.IntersectionObserver()","IntersectionObserver()")}} constructor now sets the default `rootMargin` if an empty string is passed in the associated parameter option, instead of throwing an exception ([Firefox bug 1738791](https://bugzil.la/1738791)).
#### Media, WebRTC, and Web Audio
- A number of deprecated non-standard statistics fields have been removed from the [WebRTC Statistics API](/en-US/docs/Web/API/WebRTC_Statistics_API), including: `bitrateMean`, `bitrateStdDev`, `framerateMean`, `framerateStdDev`, and `droppedFrames`.
([Firefox bug 1367562](https://bugzil.la/1367562)).
### WebDriver conformance (Marionette)
- Added the command `WebDriver:GetElementShadowRoot` to retrieve the shadow root (open or closed) hosted by a given element ([Firefox bug 1700073](https://bugzil.la/1700073)).
- Fixed a bug in `WebDriver:ExecuteScript` and `WebDriver:ExecuteAsyncScript` that caused a `cyclic object value` error when trying to return the `ShadowRoot` of an element ([Firefox bug 1489490](https://bugzil.la/1489490)).
- `WebDriver:Print` has been enhanced to support page ranges when printing documents as PDF ([Firefox bug 1678347](https://bugzil.la/1678347)).
## Changes for add-on developers
- Added {{WebExtAPIRef("runtime.getFrameId")}} that gets the frame ID of any window global or frame element from a content script ([Firefox bug 1733104](https://bugzil.la/1733104)).
## Older versions
{{Firefox_for_developers(95)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/46/index.md | ---
title: Firefox 46 for developers
slug: Mozilla/Firefox/Releases/46
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
[To test the latest developer features of Firefox, install Firefox Developer Edition](https://www.mozilla.org/firefox/developer/)Firefox 46 was released on April 26, 2016. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.
## Changes for Web developers
### Developer Tools
Highlights:
- [Dominators view in the Memory tool](https://firefox-source-docs.mozilla.org/devtools-user/memory/dominators_view/index.html)
- [Allocations view in the Performance tool](https://web.archive.org/web/20211207010022/https://firefox-source-docs.mozilla.org/devtools-user/performance/allocations/index.html)
- [One click to apply @media rule conditions in the Style Editor](https://firefox-source-docs.mozilla.org/devtools-user/style_editor/index.html#the-media-sidebar)
[All devtools bugs fixed between Firefox 45 and Firefox 46.](https://bugzilla.mozilla.org/buglist.cgi?list_id=13263754&resolution=FIXED&classification=Client%20Software&chfieldto=2016-01-25&query_format=advanced&chfield=resolution&chfieldfrom=2015-12-14&chfieldvalue=FIXED&bug_status=RESOLVED&bug_status=VERIFIED&component=Developer%20Tools&component=Developer%20Tools%3A%20about%3Adebugging&component=Developer%20Tools%3A%20Animation%20Inspector&component=Developer%20Tools%3A%20Canvas%20Debugger&component=Developer%20Tools%3A%20Computed%20Styles%20Inspector&component=Developer%20Tools%3A%20Console&component=Developer%20Tools%3A%20CSS%20Rules%20Inspector&component=Developer%20Tools%3A%20Debugger&component=Developer%20Tools%3A%20DOM&component=Developer%20Tools%3A%20Font%20Inspector&component=Developer%20Tools%3A%20Framework&component=Developer%20Tools%3A%20Graphic%20Commandline%20and%20Toolbar&component=Developer%20Tools%3A%20Inspector&component=Developer%20Tools%3A%20JSON%20Viewer&component=Developer%20Tools%3A%20Memory&component=Developer%20Tools%3A%20Netmonitor&component=Developer%20Tools%3A%20Object%20Inspector&component=Developer%20Tools%3A%20Performance%20Tools%20%28Profiler%2FTimeline%29&component=Developer%20Tools%3A%20Responsive%20Design%20Mode&component=Developer%20Tools%3A%20Scratchpad&component=Developer%20Tools%3A%20Shared%20Components&component=Developer%20Tools%3A%20Source%20Editor&component=Developer%20Tools%3A%20Storage%20Inspector&component=Developer%20Tools%3A%20Style%20Editor&component=Developer%20Tools%3A%20User%20Stories&component=Developer%20Tools%3A%20Web%20Audio%20Editor&component=Developer%20Tools%3A%20WebGL%20Shader%20Editor&component=Developer%20Tools%3A%20WebIDE&product=Firefox)
### HTML
- When faced with an invalid `type` value, {{HTMLElement("ul")}} no longer maps to `decimal`, but now behaves as if no `type` value were specified ([Firefox bug 241719](https://bugzil.la/241719)).
- The attribute `pattern` on {{HTMLElement("input")}} is now treated as {{jsxref("RegExp", "a regular expression", "", 1)}} with `"u"` (unicode) flag ([Firefox bug 1227906](https://bugzil.la/1227906)).
### CSS
- Our implementation of CSS Grids has been updated:
- The keywords `auto-fill` and `auto-fit` are now allowed in the `repeat()` function ([Firefox bug 1118820](https://bugzil.la/1118820)).
- The `true` value has been renamed to `unsafe`; this affects the properties {{cssxref("justify-content")}}, {{cssxref("align-content")}}, {{cssxref("justify-self")}}, {{cssxref("align-self")}}, {{cssxref("justify-items")}} and {{cssxref("align-items")}} ([Firefox bug 1230478](https://bugzil.la/1230478)).
- The properties {{cssxref("text-emphasis")}}, {{cssxref("text-emphasis-style")}}, {{cssxref("text-emphasis-color")}} and {{cssxref("text-emphasis-position")}} are now enabled by default ([Firefox bug 1231485](https://bugzil.la/1231485)).
- Gecko now accepts the `-webkit-` prefixed version of [some properties](https://wiki.mozilla.org/Compatibility/Mobile/Non_Standard_Compatibility); it requires to switch `layout.css.prefixes.webkit` to `true` ([Firefox bug 1213126](https://bugzil.la/1213126)).
- The experimental support of the {{cssxref("@font-face/font-display", "font-display")}} descriptor (of {{cssxref("@font-face")}}; it requires to switch `layout.css.font-display.enabled` to `true` ([Firefox bug 1157064](https://bugzil.la/1157064)).
- Added support for [`@media (-webkit-transform-3d)`](/en-US/docs/Web/CSS/@media/-webkit-transform-3d) as a media query for 3D transform support, if about:config pref `layout.css.prefixes.webkit` is set to `true` ([Firefox bug 1239799](https://bugzil.la/1239799)).
- {{cssxref("gradient/linear-gradient", "linear-gradient()")}} support for the omission of `0deg` units ([Firefox bug 1239153](https://bugzil.la/1239153)).
- Added `-webkit-filter` for web compatibility, behind the preference `layout.css.prefixes.webkit`, defaulting to `false` ([Firefox bug 1236506](https://bugzil.la/1236506)).
- \[css-align] "unsafe start" (formerly "true start") should serialize to "start" etc ([Firefox bug 1230398](https://bugzil.la/1230398)).
### JavaScript
- The ES2015 {{jsxref("RegExp.prototype.unicode", "RegExp unicode (u) flag", "", 1)}} has been implemented ([Firefox bug 1135377](https://bugzil.la/1135377)).
- The ES2015 block-level functions have been implemented ([Firefox bug 1071646](https://bugzil.la/1071646)).
- The ES2015 {{jsxref("TypedArray.prototype.sort()")}} method has been implemented ([Firefox bug 1121937](https://bugzil.la/1121937)).
- The ES2015 {{jsxref("Functions/arguments/@@iterator", "arguments[@@iterator]")}} has been implemented ([Firefox bug 1067049](https://bugzil.la/1067049)).
- The experimental [ECMAScript Shared Memory API](https://web.archive.org/web/20220124015148/https://tc39.es/ecmascript_sharedmem/shmem.html) has been implemented. See the {{jsxref("SharedArrayBuffer")}} and {{jsxref("Atomics")}} objects. To use this experimental API set `javascript.options.shared_memory` to `true` in about:config.
- Redeclaration of [`let`](/en-US/docs/Web/JavaScript/Reference/Statements/let) and [`const`](/en-US/docs/Web/JavaScript/Reference/Statements/const) variables now throws a {{jsxref("SyntaxError")}} instead of a {{jsxref("TypeError")}} as per the ECMAScript specification ([Firefox bug 1198833](https://bugzil.la/1198833)).
- In [Strict mode](/en-US/docs/Web/JavaScript/Reference/Strict_mode), setting properties on {{Glossary("primitive")}} values will now throw a {{jsxref("TypeError")}} ([Firefox bug 603201](https://bugzil.la/603201)).
- The non-standard `WeakMap.prototype.clear()` and `WeakSet.prototype.clear()` methods have been removed ([Firefox bug 1101817](https://bugzil.la/1101817)).
- The non-standard, static `RegExp.multiline` property is now deprecated ([Firefox bug 1220457](https://bugzil.la/1220457)).
- Built-in accessor function names now have a "get" or "set" prefix ([Firefox bug 1180290](https://bugzil.la/1180290), [Firefox bug 1235656](https://bugzil.la/1235656)).
- [JS1.7/JS1.8 (legacy) array comprehensions and generator comprehensions](/en-US/docs/Web/JavaScript/Reference/Deprecated_and_obsolete_features#legacy_generator_and_iterator) have been removed ([Firefox bug 1220564](https://bugzil.la/1220564)).
### Interfaces/APIs/DOM
#### DOM & HTML DOM
- The deprecated {{domxref("Window.showModalDialog()")}} method is no more available when Firefox runs in multi-process mode (e10s) ([Firefox bug 1234700](https://bugzil.la/1234700)).
- Added support for {{domxref("Document.elementsFromPoint()")}} ([Firefox bug 1164427](https://bugzil.la/1164427)).
- When a non-existent option of a {{HTMLElement("select")}} element is programmatically selected, instead of being incorrectly left unchanged, the [`selectedIndex`](/en-US/docs/Web/HTML/Element/select#selectedindex) value is now set to `-1`, the [`selectedOptions`](/en-US/docs/Web/HTML/Element/select#selectedoptions) to an empty {{domxref("HTMLCollection")}}, and [`value`](/en-US/docs/Web/HTML/Element/select#value) to an empty string ([Firefox bug 1203668](https://bugzil.la/1203668)).
#### Canvas
- The remaining parts of the experimental {{domxref("OffscreenCanvas")}} API has been implemented; new features: {{domxref("OffscreenCanvas.OffscreenCanvas", "OffscreenCanvas()")}} constructor, `OffscreenCanvas.toBlob()`, and {{domxref("OffscreenCanvas.transferToImageBitmap()")}}. To use this experimental API set `gfx.offscreencanvas.enabled` to `true` in about:config ([Firefox bug 1172796](https://bugzil.la/1172796)).
- The {{domxref("ImageBitmap.close()")}} method is now supported ([Firefox bug 1172796](https://bugzil.la/1172796)).
- A new {{domxref("ImageBitmapRenderingContext")}} rendering context is now implemented. Use `"bitmaprenderer"` with {{domxref("OffscreenCanvas.getContext()")}} or {{domxref("HTMLCanvasElement.getContext()")}} to obtain this context. ([Firefox bug 1172796](https://bugzil.la/1172796)).
#### WebGL
- The {{domxref("WEBGL_compressed_texture_etc")}} extension has been implemented, allowing the use of [ETC2 compressed texture formats](https://en.wikipedia.org/wiki/Ericsson_Texture_Compression) ([Firefox bug 917505](https://bugzil.la/917505)). To use this extension, set the preference `webgl.enable-draft-extensions` to `true` in about:config.
#### IndexedDB
_No change._
#### Service Workers
- {{domxref("FetchEvent.request")}} is now non-nullable (see [Firefox bug 1238213](https://bugzil.la/1238213).)
- {{domxref("Navigator.serviceWorker")}} has now been marked as SameObject (see [Firefox bug 1238205](https://bugzil.la/1238205).)
- {{domxref("ExtendableMessageEvent.ports")}} has now been marked as SameObject (see [Firefox bug 1238225](https://bugzil.la/1238225).)
#### Fetch
- {{domxref("Request.mode")}} now has a new value available, `navigate`, for supporting requests generated while navigating between documents (see [Firefox bug 1209081](https://bugzil.la/1209081).)
#### WebRTC
- The {{domxref("RTCPeerConnection.createOffer()")}} method now supports the VP9 video codec, although this is disabled by default. To enable it, set the preference `media.peerconnection.video.vp9_enabled` to `true` in `about:config`. When enabled, VP9 is the preferred codec; previously VP8 was preferred ([Firefox bug 1242324](https://bugzil.la/1242324)).
- The method {{domxref("RTCRtpSender.setParameters()")}} has been added to allow changing the values of parameters after the {{domxref("RTCRtpSender")}} was initially created.
#### New APIs
- In SVG, the {{domxref("SVGStyleElement")}} interface now implements the `LinkStyle` mixin ) [Firefox bug 1239128](https://bugzil.la/1239128).
#### Miscellaneous
- The asynchronous {{domxref("FileReader")}} is now available in Web workers ([Firefox bug 901097](https://bugzil.la/901097)).
- Our experimental implementation of [Web Animations API](/en-US/docs/Web/API/Web_Animations_API) has been updated:
- The `AnimationEffectTimingReadOnly` dictionary and {{domxref("AnimationEffect/getTiming", "AnimationEffectReadOnly.timing")}} have been implemented ([Firefox bug 1214536](https://bugzil.la/1214536)).
- The [Permissions API](/en-US/docs/Web/API/Permissions_API) has now been enabled by default, for all release versions, not just Nightly as it previously was ([Firefox bug 1221106](https://bugzil.la/1221106).)
- Sanitization of WOFF fonts has been loosened a bit ([Firefox bug 1244693](https://bugzil.la/1244693)).
### MathML
_No change._
### SVG
_No change._
### Audio/Video
_No change._
## HTTP
_No change._
## Networking
- Support of {{rfc(7686)}} has been added: by default there is no attempt to resolve domain with the TLD `.onion`. This is controlled by the preference `network.dns.blockDotOnion`. Add-ons supporting Tor can swap this pref. ([Firefox bug 1228457](https://bugzil.la/1228457))
## Security
_No change._
## Changes for add-on and Mozilla developers
### Interfaces
_No change._
### XUL
_No change._
### JavaScript code modules
_No change._
### XPCOM
_No change._
### Other
_No change._
## Older versions
{{Firefox_for_developers(45)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/60/index.md | ---
title: Firefox 60 for developers
slug: Mozilla/Firefox/Releases/60
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 60 that will affect developers. Firefox 60 was released on May 9, 2018.
## Stylo comes to Firefox for Android in 60
[Firefox's new parallel CSS engine](https://hacks.mozilla.org/2017/08/inside-a-super-fast-css-engine-quantum-css-aka-stylo/) — also known as **Quantum CSS** or **Stylo** — which was [first enabled by default in Firefox 57 for desktop](/en-US/docs/Mozilla/Firefox/Releases/57#firefox_57_firefox_quantum), has now been enabled in Firefox for Android.
## Changes for web developers
### Developer tools
- In the CSS Pane rules view (see [Examine and edit CSS](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_css/index.html)), the keyboard shortcuts for precise value increments (increase/decrease by 0.1) have changed from `Alt` + `Up`/`Down` to `Ctrl` + `Up`/`Down` on Linux and Windows, to avoid clashes with default OS-level shortcuts (see [Firefox bug 1413314](https://bugzil.la/1413314)).
- Also in the CSS Pane rules view, [CSS variable names](/en-US/docs/Web/CSS/Using_CSS_custom_properties) will now auto-complete ([Firefox bug 1422635](https://bugzil.la/1422635)). If you enter `var(` into a property value and then type a dash (`-`), any variables you have declared in your CSS will then appear in an autocomplete list.
- In [Responsive Design Mode](https://firefox-source-docs.mozilla.org/devtools-user/responsive_design_mode/index.html), a _Reload when…_ dropdown has been added to allow users to enable/disable automatic page reloads when touch simulation is toggled, or simulated user agent is changed. See [Controlling page reload behavior](https://firefox-source-docs.mozilla.org/devtools-user/responsive_design_mode/index.html#controlling-page-reload-behavior) for more details ([Firefox bug 1428816](https://bugzil.la/1428816)).
- The `view_source.tab` preference has been removed so you can no longer toggle [View Source](https://firefox-source-docs.mozilla.org/devtools-user/view_source/index.html) mode between appearing in a new tab or new window. Page sources will always appear in new tabs from now on ([Firefox bug 1418403](https://bugzil.la/1418403)).
### HTML
Pressing the Enter key in `designMode` and `contenteditable` now inserts `<div>` elements when the caret is in an inline element or text node which is a child of a block level editing host — instead of inserting `<br>` elements like it used to. If you want to use the old behavior on your app, you can do it with `document.execCommand()`. See [Differences in markup generation](/en-US/docs/Web/HTML/Global_attributes/contenteditable#differences_in_markup_generation) for more details (also see [Firefox bug 1430551](https://bugzil.la/1430551)).
### CSS
- The {{cssxref("align-content")}}, {{cssxref("align-items")}}, {{cssxref("align-self")}}, {{cssxref("justify-content")}}, and {{cssxref("place-content")}} property values have been updated as per the latest [CSS Box Alignment Module Level 3](https://drafts.csswg.org/css-align-3/) spec ([Firefox bug 1430817](https://bugzil.la/1430817)).
- The {{cssxref("paint-order")}} property has been implemented ([Firefox bug 1426146](https://bugzil.la/1426146)).
### SVG
_No changes._
### JavaScript
- ECMAScript 2015 modules have been enabled by default in ([Firefox bug 1438139](https://bugzil.la/1438139)). See [ES6 In Depth: Modules](https://hacks.mozilla.org/2015/08/es6-in-depth-modules/) and [ES modules: A cartoon deep dive](https://hacks.mozilla.org/2018/03/es-modules-a-cartoon-deep-dive/) for more information, or consult MDN reference docs:
- [`<script src="main.js" type="module">`](/en-US/docs/Web/HTML/Element/script#type) and [`<script nomodule src="fallback.js">`](/en-US/docs/Web/HTML/Element/script#nomodule)
- [`import`](/en-US/docs/Web/JavaScript/Reference/Statements/import) and [`export`](/en-US/docs/Web/JavaScript/Reference/Statements/export) statements.
- The {{jsxref("Array.prototype.values()")}} method has been added again ([Firefox bug 1420101](https://bugzil.la/1420101)). Make sure your code doesn't have any custom implementation of this method.
### APIs
#### New APIs
- The [Web Authentication API](/en-US/docs/Web/API/Web_Authentication_API) has been enabled in ([Firefox bug 1432542](https://bugzil.la/1432542)).
#### DOM
- In the [Web Authentication API](/en-US/docs/Web/API/Web_Authentication_API), the `MakePublicKeyCredentialOptions` dictionary object has been renamed `PublicKeyCredentialCreationOptions`; this change has been made in Firefox ([Firefox bug 1436473](https://bugzil.la/1436473)).
- The `dom.workers.enabled` pref has been removed, meaning workers can no longer be disabled since ([Firefox bug 1434934](https://bugzil.la/1434934)).
- The {{domxref("Document.body","body")}} property is now implemented on the {{domxref("Document")}} interface, rather than the {{domxref("HTMLDocument")}} interface ([Firefox bug 1276438](https://bugzil.la/1276438)).
- {{domxref("PerformanceResourceTiming")}} is now available in workers ([Firefox bug 1425458](https://bugzil.la/1425458)).
- The {{domxref("PerformanceObserver.takeRecords()")}} method has been implemented ([Firefox bug 1436692](https://bugzil.la/1436692)).
- The {{domxref("KeyboardEvent.keyCode")}} attribute of punctuation key becomes non-zero even if the active keyboard layout doesn't produce ASCII characters. See [these notes for more detail](/en-US/docs/Web/API/KeyboardEvent/keyCode#keycode_of_punctuation_keys_on_some_keyboard_layout). Please do **not** use `KeyboardEvent.keyCode` in new applications — use {{domxref("KeyboardEvent.key")}} or {{domxref("KeyboardEvent.code")}} instead.
- The {{domxref("Animation.updatePlaybackRate()")}} method has been implemented ([Firefox bug 1436659](https://bugzil.la/1436659)).
- New rules have been included for determining [keyCode values of punctuation keys](/en-US/docs/Web/API/KeyboardEvent/keyCode#keycode_of_punctuation_keys_on_some_keyboard_layout) ([Firefox bug 1036008](https://bugzil.la/1036008)).
- The Gecko-only options object `storage` option of the {{domxref("IDBFactory.open()")}} method (see [Experimental Gecko options object](/en-US/docs/Web/API/IDBFactory/open#experimental_gecko_options_object)) has been deprecated ([Firefox bug 1442560](https://bugzil.la/1442560)).
- [Promises](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) can now be used within [IndexedDB](/en-US/docs/Web/API/IndexedDB_API) code ([Firefox bug 1193394](https://bugzil.la/1193394)).
#### DOM events
_No changes._
#### Service workers
_No changes._
#### Media and WebRTC
- When recording or sharing media obtained using {{domxref("MediaDevices.getUserMedia", "getUserMedia()")}}, muting the camera by setting the corresponding track's {{domxref("MediaStreamTrack.enabled")}} property to `false` now turns off the camera's "in use" indicator light, to help the user more easily see that the camera is not in use ([Firefox bug 1299515](https://bugzil.la/1299515)). See [User privacy](/en-US/docs/Web/API/MediaDevices/getUserMedia#user_privacy) for more details. See also [this blog post](https://blog.mozilla.org/webrtc/better-privacy-on-camera-mute-in-firefox-60/).
- Removing a track from an {{domxref("RTCPeerConnection")}} using {{domxref("RTCPeerConnection.removeTrack", "removeTrack()")}} no longer removes the track's {{domxref("RTCRtpSender")}} from the peer connection's list of senders as reported by {{domxref("RTCPeerConnection.getSenders", "getSenders()")}} ([Firefox bug 1290949](https://bugzil.la/1290949)).
- The `RTCRtpContributingSource` and `RTCRtpSynchronizationSource` objects' timestamps were previously being reported based on values returned by {{jsxref("Date.getTime()")}}. In Firefox 60, these have been fixed to correctly use the [Performance Timing API](/en-US/docs/Web/API/Performance_API) instead ([Firefox bug 1433576](https://bugzil.la/1433576)).
- As per spec, the {{domxref("ConvolverNode.ConvolverNode","ConvolverNode()")}} constructor now throws a `NotSupportedError` {{domxref("DOMException")}} if the referenced {{domxref("AudioBuffer")}} does not have 1, 2, or 4 channels ([Firefox bug 1443228](https://bugzil.la/1443228)).
- The obsolete {{domxref("RTCPeerConnection")}} event handler {{domxref("RTCPeerConnection.removestream_event", "RTCPeerConnection.onremovestream")}} has been removed; by now you should be using {{domxref("MediaStream/removetrack_event", "removetrack")}} events instead ([Firefox bug 1442385](https://bugzil.la/1442385)).
- The primary name for {{domxref("RTCDataChannel")}} is now in fact `RTCDataChannel`, instead of being an alias for `DataChannel`. The name `DataChannel` is no longer supported ([Firefox bug 1173851](https://bugzil.la/1173851)).
#### Canvas and WebGL
- If the `privacy.resistFingerprinting` preference is set to `true`, the {{domxref("WEBGL_debug_renderer_info")}} WebGL extension will be disabled from now on ([Firefox bug 1337157](https://bugzil.la/1337157)).
### CSSOM
_No changes._
### HTTP
- `SameSite` cookies are now supported ([Firefox bug 795346](https://bugzil.la/795346)). See {{HTTPHeader("Set-Cookie")}} for more information.
### Security
The {{httpheader("X-Content-Type-Options")}} header, when set to `no-sniff`, now follows the specification for JavaScript MIME types. In particular, `text/json` and `application/json` are no longer valid values ([Firefox bug 1431095](https://bugzil.la/1431095)).
### Plugins
_No changes._
### Other
Fetches that include credentials can now share connections with fetches that don't include credentials. For example, if the same origin requests some web fonts as well as some credentialed user data from the same CDN, both could share a connection, potentially leading to a quicker turnaround ([Firefox bug 1363284](https://bugzil.la/1363284)).
## Removals from the web platform
### HTML
_No changes._
### CSS
- The proprietary {{cssxref("-moz-user-input")}} property's `enabled` and `disabled` values are no longer available ([Firefox bug 1405087](https://bugzil.la/1405087)).
- The proprietary `-moz-border-top-colors`, `-moz-border-right-colors`, `-moz-border-bottom-colors`, and `-moz-border-left-colors` properties have been removed from the platform completely ([Firefox bug 1429723](https://bugzil.la/1429723)).
### JavaScript
The non-standard [expression closure](/en-US/docs/Web/JavaScript/Reference/Deprecated_and_obsolete_features#statements_2) syntax has been removed ([Firefox bug 1426519](https://bugzil.la/1426519)).
### APIs
_No changes._
### SVG
_No changes._
### Other
_No changes._
## Changes for add-on and Mozilla developers
### WebExtensions
Theme API:
- headerURL is now optional
- When creating a browser [theme](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/theme), any {{cssxref("text-shadow")}} applied to the header text is removed if no `headerURL` is specified (see [Firefox bug 1404688](https://bugzil.la/1404688)).
- New properties are supported:
- **tab_line**
- **tab_selected**
- **popup**
- **popup_border**
- **popup_text**
- **tab_loading**
- **icons**
- **icons_attention**
- **frame_inactive**
- **button_background_active**
- **button_background_hover**
## Older versions
{{Firefox_for_developers(59)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/40/index.md | ---
title: Firefox 40 for developers
slug: Mozilla/Firefox/Releases/40
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
[To test the latest developer features of Firefox, install Firefox Developer Edition](https://www.mozilla.org/firefox/developer/) Firefox 40 was released on August 11, 2015. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.
## Changes for Web developers
### Developer Tools
Highlights:
- [Improvements to the Animations view](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/work_with_animations/index.html#firefox-40)
- [Get help from MDN for CSS property syntax](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_css/index.html#get-help-for-css-properties)
- [Edit filters in the Page Inspector](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/edit_css_filters/index.html)
- [Web Console now shows messages from workers](https://firefox-source-docs.mozilla.org/devtools-user/web_console/index.html#console-api-messages)
- [Filter requests by URL in the Network Monitor](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/index.html#filtering-by-url)
- [Many new context menu options in the Network Monitor](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/index.html#context-menu)
- [Show when network resources are fetched from the browser cache](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/index.html#network-request-fields)
- [Filter rules in the Page Inspector](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_css/index.html#filtering-rules)
More:
- [Break at debugger; statements in unnamed eval sources](https://firefox-source-docs.mozilla.org/devtools-user/debugger/how_to/debug_eval_sources/index.html)
- [Copy URL/Open in New Tab context menu items for Debugger source list pane](https://firefox-source-docs.mozilla.org/devtools-user/debugger/ui_tour/index.html#source-list-pane)
- [console.dirxml support in the Web Console](https://firefox-source-docs.mozilla.org/devtools-user/web_console/index.html#log-messages)
- [Style Editor: "Open Link In New Tab" item added to stylesheet list](https://firefox-source-docs.mozilla.org/devtools-user/style_editor/index.html#the-style-sheet-pane)
- [Inspector selector search now includes class/id results even without css prefix](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_html/index.html#searching)
- [Tooltips in box-model view saying which CSS rule caused the value](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_the_box_model/index.html#the-box-model-view)
- [Switch between color unit format in the Inspector using Shift+click](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/inspect_and_select_colors/index.html)
- [Implement "Scroll Into View" menu item for the Inspector](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_html/index.html#element-popup-menu)
- [Linkify url/id/resource attributes in the Inspector](https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_html/index.html#element-popup-menu)
- [IP address tooltip in the Network Monitor](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/index.html#network-request-fields)
Everything: [all devtools bugs fixed between Firefox 39 and Firefox 40](https://bugzilla.mozilla.org/buglist.cgi?resolution=FIXED&classification=Client%20Software&chfieldto=2015-05-11&query_format=advanced&chfield=resolution&chfieldfrom=2015-03-31&chfieldvalue=FIXED&bug_status=RESOLVED&bug_status=VERIFIED&component=Developer%20Tools&component=Developer%20Tools%3A%203D%20View&component=Developer%20Tools%3A%20Canvas%20Debugger&component=Developer%20Tools%3A%20Console&component=Developer%20Tools%3A%20Debugger&component=Developer%20Tools%3A%20Framework&component=Developer%20Tools%3A%20Graphic%20Commandline%20and%20Toolbar&component=Developer%20Tools%3A%20Inspector&component=Developer%20Tools%3A%20Memory&component=Developer%20Tools%3A%20Netmonitor&component=Developer%20Tools%3A%20Object%20Inspector&component=Developer%20Tools%3A%20Performance%20Tools%20%28Profiler%2FTimeline%29&component=Developer%20Tools%3A%20Responsive%20Mode&component=Developer%20Tools%3A%20Scratchpad&component=Developer%20Tools%3A%20Source%20Editor&component=Developer%20Tools%3A%20Storage%20Inspector&component=Developer%20Tools%3A%20Style%20Editor&component=Developer%20Tools%3A%20User%20Stories&component=Developer%20Tools%3A%20Web%20Audio%20Editor&component=Developer%20Tools%3A%20WebGL%20Shader%20Editor&component=Developer%20Tools%3A%20WebIDE&product=Firefox&list_id=12283503).
### CSS
- Prefixed rules (`-moz-`) for {{cssxref("text-decoration-color")}}, {{cssxref("text-decoration-line")}}, and {{cssxref("text-decoration-style")}} have been removed ([Firefox bug 1097922](https://bugzil.la/1097922)).
- The property {{cssxref("text-align")}} now supports the `match-parent` value ([Firefox bug 645642](https://bugzil.la/645642)).
- In Quirks Mode, {{cssxref("empty-cells")}} now defaults to `show`, like in standard mode ([Firefox bug 1020400](https://bugzil.la/1020400)).
- The {{cssxref("-moz-orient")}} non-standard property, used to style {{HTMLElement('meter')}} and {{HTMLElement('progress')}} element has been adapted for vertical writing-modes: the value `auto` has been dropped and the values `inline` and `block` added, with `inline` being the new default value ([Firefox bug 1028716](https://bugzil.la/1028716)).
- The property {{cssxref("font-size-adjust")}} has been fixed so that `0` is treated as a multiplier (leading to a `0` height for the font, hence hiding it) instead of the `none` value (leading to no adjustment, or a `1.0` value) ([Firefox bug 1144885](https://bugzil.la/1144885)).
- Fix text-overflow doesn't work in vertical writing mode ([Firefox bug 1117227](https://bugzil.la/1117227)).
### HTML
_No change._
### JavaScript
- Unreachable code after {{jsxref("Statements/return", "return")}} statement (including unreachable expression after {{jsxref("Statements/return", "semicolon-less return statements", "#Automatic_semicolon_insertion", 1)}}) will now show a warning in the console ([Firefox bug 1005110](https://bugzil.la/1005110), [Firefox bug 1151931](https://bugzil.la/1151931)).
- {{jsxref("Symbol.match")}} has been added ([Firefox bug 1054755](https://bugzil.la/1054755)).
- Passing an object which has a property named {{jsxref("Symbol.match")}} with a {{Glossary("truthy")}} value to {{jsxref("String.prototype.startsWith")}}, {{jsxref("String.prototype.endsWith")}}, and `String.prototype.contains` now throws a {{jsxref("TypeError")}} ([Firefox bug 1054755](https://bugzil.la/1054755)).
- {{jsxref("RegExp")}} function returns pattern itself if called without {{jsxref("Operators/new", "new")}} and pattern object has a property named {{jsxref("Symbol.match")}} with a {{Glossary("truthy")}} value, and the pattern object's `constructor` property equals to {{jsxref("RegExp")}} function. ([Firefox bug 1147817](https://bugzil.la/1147817)).
- Support for the non-standard JS1.7 destructuring for-in has been dropped ([Firefox bug 1083498](https://bugzil.la/1083498)).
- [Non-standard initializer expressions](/en-US/docs/Web/JavaScript/Reference/Errors/Invalid_for-in_initializer) in [`for...in`](/en-US/docs/Web/JavaScript/Reference/Statements/for...in) loops are now ignored and will present a warning in the console. ([Firefox bug 748550](https://bugzil.la/748550) and [Firefox bug 1164741](https://bugzil.la/1164741)).
- [`\u{xxxxxx}`](/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#unicode_code_point_escapes) Unicode code point escapes have been added ([Firefox bug 320500](https://bugzil.la/320500)).
- {{jsxref("String.prototype.includes", "String.prototype.contains", "#String.prototype.contains")}} has been replaced with {{jsxref("String.prototype.includes")}}, `String.prototype.contains` is kept as an alias ([Firefox bug 1102219](https://bugzil.la/1102219)).
- If the {{jsxref("DataView")}} constructor is called as a function without the {{ jsxref("Operators/new", "new") }} operator, a {{jsxref("TypeError")}} is now thrown as per the ES2015 specification.
- An issue regressed in Firefox 21, where proxyfied arrays without the `get` trap were not working properly, has been fixed. If the `get` trap in a {{jsxref("Proxy")}} was not defined, {{jsxref("Array.length")}} returned `0` and the `set` trap didn't get called. A workaround was to add the `get` trap even if was not necessary in your code. This issue has been fixed now ([Firefox bug 895223](https://bugzil.la/895223)).
- `WeakMap.prototype` and `WeakSet.prototype` have been updated to be just ordinary objects, per ES2015 specification ([Firefox bug 1055473](https://bugzil.la/1055473)).
### Interfaces/APIs/DOM
#### New APIs
- The [Push API](/en-US/docs/Web/API/Push_API) has been experimentally implemented ([Firefox bug 1038811](https://bugzil.la/1038811)). Controlled by the `services.push.enabled` pref, it is disabled by default.
#### Web Animations API
Improvement in our experimental Web Animations implementation, mostly to match latest spec changes:
- {{domxref("Animation/currentTime", "AnimationPlayer.currentTime")}} now can also be set ([Firefox bug 1072037](https://bugzil.la/1072037)).
- `Animatable.getAnimationPlayers()`, available on {{domxref("Element")}} has been renamed to {{domxref("Element.getAnimations()")}} ([Firefox bug 1145246](https://bugzil.la/1145246)).
- `Animation` and `AnimationEffect` have been merged into the newly created `KeyframeEffectReadOnly` ([Firefox bug 1153734](https://bugzil.la/1153734)).
- `AnimationPlayer` has been renamed to {{domxref("Animation")}} ([Firefox bug 1154615](https://bugzil.la/1154615)).
- {{domxref("AnimationTimeline")}} is now an abstract class, with {{domxref("DocumentTimeline")}} its only implementation ([Firefox bug 1152171](https://bugzil.la/1152171)).
#### CSSOM
- The CSS Font Loading API is now enabled by default in Nightly and Developer Edition releases ([Firefox bug 1088437](https://bugzil.la/1088437)). It is still deactivated by default in Beta and Release browsers.
- The `CSSCharsetRule` interface has been removed and such objects are no longer available in CSSOM ([Firefox bug 1148694](https://bugzil.la/1148694)). This matches the spec (recently adapted) and Chrome behavior.
#### WebRTC
- WebRTC: the {{domxref("RTCPeerConnection.negotiationneeded_event", "negotiationneeded")}} event is now also sent for initial negotiations, not only for re-negotiations ([Firefox bug 1149838](https://bugzil.la/1149838)).
#### DOM & HTML DOM
- When unable to parse the [`srcset`](/en-US/docs/Web/HTML/Element/image#srcset), the {{domxref("HTMLImageElement.currentSrc")}} method doesn't return `null` anymore but `""`, as requested by the latest specification ([Firefox bug 1139560](https://bugzil.la/1139560)).
- Like for images, Firefox now throttles {{domxref("Window.requestAnimationFrame()")}} for non-visible {{HTMLElement("iframe")}} ([Firefox bug 1145439](https://bugzil.la/1145439)).
- {{domxref("Navigator.taintEnabled")}} is no longer available for Web workers ([Firefox bug 1154878](https://bugzil.la/1154878)).
#### Web Audio API
New extensions to the [Web Audio API](/en-US/docs/Web/API/Web_Audio_API):
- The {{domxref("BaseAudioContext/state", "AudioContext.state")}} and {{domxref("BaseAudioContext.statechange_event", "AudioContext.onstatechange")}} properties as well as the methods {{domxref("AudioContext.suspend()")}}, {{domxref("AudioContext.resume()")}}, and {{domxref("AudioContext.close()")}} have been added ([Firefox bug 1094764](https://bugzil.la/1094764)).
- {{domxref("AudioBufferSourceNode")}} now implements the {{domxref("AudioBufferSourceNode.detune")}} [k-rate](/en-US/docs/Web/API/AudioParam#k-rate) attribute ([Firefox bug 1153783](https://bugzil.la/1153783)).
#### Web Workers
- Slight improvement in our [Service Worker API](/en-US/docs/Web/API/Service_Worker_API): the {{domxref("ServiceWorkerRegistration.update()", "update()")}} method has been moved from {{domxref("ServiceWorkerGlobalScope")}} to {{domxref("ServiceWorkerRegistration")}} ([Firefox bug 1131350](https://bugzil.la/1131350)).
- {{domxref("ServiceWorkerRegistration")}} is now available in Web workers ([Firefox bug 1131327](https://bugzil.la/1131327)).
- {{domxref("DataStore")}} is now available in Web workers ([Firefox bug 916196](https://bugzil.la/916196)).
#### IndexedDB
- {{domxref("IDBTransaction")}} are now non-durable by default ([Firefox bug 1112702](https://bugzil.la/1112702)). This favors performance over reliability and matches what other browsers are doing. For more information, read our [durability definition](/en-US/docs/Web/API/IndexedDB_API/Basic_Terminology#durable).
#### Dev Tools
- The property {{domxref("console/timeStamp_static", "console.timeStamp()")}} has been added ([Firefox bug 922221](https://bugzil.la/922221)).
### MathML
_No change._
### SVG
_No change._
### Audio/Video
_No change._
## Networking
_No change._
## Security
- Using an asterisk (`*`) in a {{Glossary("CSP")}} does not include the schemes `data:`, `blob:` or `:filesystem` anymore when matching source expressions. So those schemes now need to be explicitly defined within the related header to match the CSP ([Firefox bug 1086999](https://bugzil.la/1086999)).
## Changes for add-on and Mozilla developers
### XUL
- It is no longer possible to create transparent top-level windows [Firefox bug 1162649](https://bugzil.la/1162649).
### JavaScript code modules
- Dict.jsm has been removed [Firefox bug 1123309](https://bugzil.la/1123309). Use {{jsxref("Map")}} instead.
### XPCOM
- The `nsIClassInfo.implementationLanguage` attribute has been removed, along with the `nsClassInfo::GetImplementationLanguage()` function.
- The following XPCOM interfaces have been removed; you should use the standard HTML interfaces instead:
- `nsIDOMHTMLBRElement`
- `nsIDOMDivElement`
- `nsIDOMHTMLHeadingElement`
- `nsIDOMHTMLTableCaptionElement`
- `nsIDOMHTMLTableElement`
- `nsIDOMHTMLTitleElement`
### Other
- Places Keywords API has been deprecated and will be removed soon ([Firefox bug 1140395](https://bugzil.la/1140395)).
- The automated testing system now supports skipping individual test functions. See [running conditional tests](https://firefox-source-docs.mozilla.org/testing/xpcshell/index.html#conditionally-running-a-test) in XPCShell testing.
## Older versions
{{Firefox_for_developers('39')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/9/index.md | ---
title: Firefox 9 for developers
slug: Mozilla/Firefox/Releases/9
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
Firefox 9 was released for Windows on December 20, 2011. Mac and Linux version 9.0.1, which fixed a crashing bug discovered at the last minute, were released on December 21, 2011.
## Changes for web developers
### HTML
- The `value` attribute of {{ HTMLElement("li") }} now can be negative. Previously negative values were converted to 0.
- You can now [specify the start and stop time of media](/en-US/docs/Learn/HTML/Multimedia_and_embedding/Video_and_audio_content#specifying_playback_range) in the URI of the media when using {{ HTMLElement("audio") }} and {{ HTMLElement("video") }} elements.
- {{ HTMLElement("input") }} and {{ HTMLElement("textarea") }} elements [now respect the value of the `lang` attribute](/en-US/docs/Web/HTML/Global_attributes/spellcheck#controlling_the_spellchecker_language) when invoking the spell checker.
- Firefox on Android now lets users snap photos with their phone's camera without leaving the browser when the {{ HTMLElement("input") }} element is used with `type="file"` and `accept="image/*"`.
- Windows Vista style PNG ICO images are now supported.
- Drawing images that use the [`crossorigin`](/en-US/docs/Web/HTML/Attributes/crossorigin) attribute to request CORS access no longer incorrectly [taint the canvas](/en-US/docs/Web/HTML/CORS_enabled_image#what_is_a_.22tainted.22_canvas.3f) when CORS is granted.
- The value of the [`rowspan`](/en-US/docs/Web/HTML/Element/td#rowspan) attribute may now be as large as 65,534, up from 8190.
### CSS
- The {{ cssxref("font-stretch") }} property is now supported.
- The {{ cssxref("columns") }} property is now supported, with the `-moz` prefix. This is a shorthand for the following properties: {{ cssxref("column-width") }} and {{ cssxref("column-count") }}.
- When a stylesheet included using the {{ HTMLElement("link") }} element has been fully loaded and parsed (but not yet applied to the document), a [`load` event](/en-US/docs/Web/HTML/Element/link#stylesheet_load_events) is now fired. Also, if an error occurs processing a style sheet, an `error` event is fired.
- You can now specify overflow settings for both the left and right edges of content using a new two-value syntax for {{ cssxref("text-overflow") }}.
### JavaScript
_No change._
### DOM
- [Using fullscreen mode](/en-US/docs/Web/API/Fullscreen_API)
- : The new fullscreen API provides a way to present content using the entire screen, with no browser interface. This is great for video and games. This API is currently experimental and prefixed.
<!---->
- The {{ domxref("Node.contains()") }} method is now implemented; this lets you determine if a given node is a descendant of another node.
- The {{ domxref("Node.parentElement") }} attribute has been implemented; this returns the parent {{ domxref("Element") }} of a DOM node, or `null` if the parent isn't an element.
- DOM Level 3 [composition events](/en-US/docs/Web/API/CompositionEvent) are now supported.
- The {{ domxref("Document.scripts") }} attribute has been implemented; this returns an {{ domxref("HTMLCollection") }} of all the {{ HTMLElement("script") }} elements on the document.
- The {{ domxref("Document.queryCommandSupported()") }} method has been implemented.
- The set of events that can be listened for on {{ HTMLElement("body") }} elements has been revised to match the latest draft of the HTML5 specification. The list of events in the [DOM event reference](/en-US/docs/Web/Events) reflects which events can be listened for on {{ HTMLElement("body") }}.
- The `readystatechange` event is now fired only on the {{ domxref("Document") }}, as intended.
- Event handlers are now implemented as standard IDL interfaces. For most cases, this won't affect content, but there are exceptions.
- A new response type, "`moz-json`", has been added to `XMLHttpRequest`, letting `XMLHttpRequest` automatically parse [JSON](/en-US/docs/Glossary/JSON) strings for you; when you request this type, a returned JSON string is parsed, so that the value of the `response` property is the resulting JavaScript object.
- [`XMLHttpRequest` "progress" events](/en-US/docs/Web/API/XMLHttpRequest_API/Using_XMLHttpRequest#monitoring_progress) are now reliably sent for every chunk of data received; in the past it was possible for the last chunk of data received to not fire a "progress" event. Now you can track progress by following only "progress" events, instead of also having to monitor "load" events to detect the receipt of the last chunk of data.
- In the past, calling [`addEventListener()`](/en-US/docs/Web/API/EventTarget/addEventListener) with a `null` listener would throw an exception. Now it returns without error and with no effect.
- The new {{ domxref("navigator.doNotTrack") }} property lets your content easily determine whether or not the user has enabled their do-no-track preference; if this value is "yes", you should not track the user.
- {{ domxref("Range") }} and {{ domxref("Selection") }} objects now behave according to their specifications when {{ domxref("Text.splitText()", "splitText()") }} and {{ domxref("Node.normalize", "normalize()") }} are called.
- The value of {{ domxref("Node.ownerDocument") }} for doctype nodes is now the document on which [`createDocumentType()`](/en-US/docs/Web/API/DOMImplementation/createDocumentType) was called to create the node, instead of `null`.
- `window.navigator.taintEnabled` has been removed; it has not been supported in many years.
### Workers
- Workers implemented in blob URLs were broken in Firefox 8, and work again starting in Firefox 9.
### WebGL
- The [WebGL](/en-US/docs/Web/API/WebGL_API) context `drawingBufferWidth` and `drawingBufferHeight` attributes are now supported.
### MathML
- The non-standard `restyle` value for the `actiontype` attribute on {{ MathMLElement("maction") }} elements has been removed.
- While still unsupported, using the `mlabeledtr` element no longer breaks rendering completely. See [Firefox bug 689641](https://bugzil.la/689641) for progress on actual support of this element.
### Networking
- You can now send the contents of [JavaScript typed arrays](/en-US/docs/Web/JavaScript/Guide/Typed_arrays) (that is, the contents of an [`ArrayBuffer`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer) object) [using XMLHttpRequest](/en-US/docs/Web/API/XMLHttpRequest_API/Using_XMLHttpRequest#sending_typed_arrays_as_binary_data).
- WebSocket connections now permit non-characters in otherwise valid UTF-8 data frames to be received, instead of failing.
- The HTTP `Accept` header for XSLT requests has been changed to "\*/\*" for simplicity. Since fetching XSLT has always fallen back to "\*/\*" anyway, it made sense to simplify the initial request.
- Attempts by a server to use the `301 Moved Permanently` or `307 Temporary Redirect` response codes to redirect the user to a `javascript:` URI now [result in a "bad connection" error](/en-US/docs/Web/HTTP#more_on_redirection_responses) instead of actually redirecting. This prevents certain types of cross-site scripting attacks.
- Content served with an empty {{ HTTPHeader("Content-Disposition") }} were previously treated as if the {{ HTTPHeader("Content-Disposition") }} were "attachment"; this didn't always work as expected. These are now handled as if the {{ HTTPHeader("Content-Disposition") }} were "inline".
- The default maximum size of an item in the disk cache has been increased to 50 MB; previously, only items up to 5 MB were cached.
### Developer tools
- The web console now supports basic [string substitutions](https://firefox-source-docs.mozilla.org/devtools-user/web_console/index.html#string-substitutions) in its logging methods.
- You can now [create visually nested blocks of output](https://firefox-source-docs.mozilla.org/devtools-user/web_console/index.html#using-groups-in-the-console) in the web console, to help make it easier to read.
## Changes for Mozilla and add-on developers
See [Updating add-ons for Firefox 9](/en-US/docs/Mozilla/Firefox/Releases/9/Updating_add-ons) for an overview of the changes you may need to make to get your add-ons working in Firefox 9.
### XUL
- The `<xul:tab>` element now has a `pending` attribute, whose value is `true`, when the tab is in the process of being restored by the session store service. This can be used for styling the tab in themes. The attribute isn't present on tabs that aren't pending.
- The `<xul:tab>` element now has an `unread` attribute, whose value is `true`, when the tab has changed since the last time it was the active tab or if it hasn't been selected since the current session began. The attribute isn't present on tabs that are not unread.
- You can now use a `<xul:panel>` as a drag image for DOM drag and drop operations. This lets you use the standard drag & drop API for [drag and drop of XUL content](/en-US/docs/Web/API/HTML_Drag_and_Drop_API/Drag_operations#using_xul_panels_as_drag_images).
- The `<xul:notificationbox>` element's `appendNotification`) method now lets you specify a callback that gets called for interesting events related to the notification box. Currently, the only event is "removed", which tells you the box has been removed from its window.
### JavaScript code module changes
- `FileUtils.jsm` now has a `File` constructor that returns an `nsIFile` object representing a file specified by its pathname.
### Service changes
- The content preference service now handles private mode browsing (see [Firefox bug 679784](https://bugzil.la/679784)).
### NSPR
- NSPR now has an "append" module, which lets you append new data to the end of an existing log.
### Interface changes
#### Removed interfaces
- `nsIGlobalHistory3` has been removed during streamlining of the Places and DocShell code.
#### Miscellaneous interface changes
- The `nsISound` interface has a new constant, `EVENT_EDITOR_MAX_LEN`. The allows for playing the system sound for when more characters than the maximum allowed are typed into a text field. Currently, this is only used on Windows.
- The `nsIScriptError2` interface has new `timeStamp` and `innerWindowID` properties; in addition, the `initWithWindowID()` method now takes an inner window ID instead of an outer window ID.
- The `nsIBidiKeyboard.haveBidiKeyboards` attribute has been added; this lets you determine if the system has at least one keyboard installed for each direction: left-to-right and right-to-left.
- The new `nsIEditor.isSelectionEditable` attribute lets you determine if the current selection anchor is editable. This helps to support cases where only parts of the document are editable, by letting you see if the current selection is in an editable section.
- The `nsIBrowserHistory.registerOpenPage()` and `nsIBrowserHistory.unregisterOpenPage()` methods have been removed as part of a performance overhaul in the Places system. You can use the corresponding methods in `mozIPlacesAutoComplete` instead.
- The `nsIDOMWindowUtils.wrapDOMFile()` method has been added; this returns a DOM {{ domxref("File") }} object for a given `nsIFile`.
- The `nsIChromeFrameMessageManager.removeDelayedFrameScript()` method was added to support removing delayed load scripts. Bootstrapped add-ons should use this, at shutdown, to remove any scripts it loaded using `nsIChromeFrameMessageManager.loadFrameScript()` with the delayed load flag set. This is exposed to add-ons as `browser.messageManager.removeDelayedFrameScript()`.
- The `nsIAppStartup` interface has a new `interrupted` attribute, which lets you know if the startup process was interrupted at any point by an interactive prompt. This can be helpful, for example, when timing startups during performance evaluation, to be able to drop numbers from sessions that were interrupted.
- The `nsIEditorSpellCheck` interface has been revised to support per-site selection of spell checker dictionaries.
### IDL parser
The IDL parser no longer includes support for the never fully-implemented notion of unique pointers.
### Build system changes
- The `--enable-application=standalone` option for building standalone XPConnect has been removed; it hasn't worked since 2007 anyway.
- Support for building Necko and Transformiix XSLT standalone has been removed; you can no longer use `--enable-application=network` or `--enable-application=content/xslt`.
- The build system now looks for `.mozconfig` at `$topsrcdir/.mozconfig` or `$topsrcdir/mozconfig`, and nowhere else, unless you override the `.mozconfig` path using the `MOZCONFIG` environment variable.
- The `xpidl` utility has been replaced in the SDK with `pyxpidl`.
### Other changes
- The spell checker no longer has an arbitrary 130-character word-length limit on the length of words it will attempt to spell check. This limit was previously in place to prevent crashes that were occurring in the spell checker, but the underlying bugs have since been fixed.
- You can now register components to add features to the {{ domxref("window.navigator") }} object by using the "JavaScript-navigator-property" category.
## See also
{{Firefox_for_developers('8')}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases/9 | data/mdn-content/files/en-us/mozilla/firefox/releases/9/updating_add-ons/index.md | ---
title: Updating add-ons for Firefox 9
slug: Mozilla/Firefox/Releases/9/Updating_add-ons
page-type: guide
---
{{FirefoxSidebar}}
Firefox 9 doesn't have a lot of changes that should be compatibility issues for add-on developers. However, there are a few possible items that might trip you up, so let's take a look.
## Do you need to do anything at all?
If your add-on is distributed on [addons.mozilla.org](https://addons.mozilla.org/en-US/firefox/) (AMO), it's been checked by an automated compatibility verification tool. Add-ons that don't use APIs that changed in Firefox 8, and have no binary components (which need to be recompiled for every major Firefox release), have automatically been updated on AMO to indicate that they work in Firefox 9.
So you should start by visiting AMO and looking to see if your add-on needs any work done at all.
> **Note:** You should still test your add-on on Firefox 9, even if it's been automatically upgraded. There are edge cases that may not be automatically detected.
Once you've confirmed that you need to make changes, come on back to this page and read on.
## Bootstrapped add-ons can remove delayed-load scripts
If your add-on uses `nsIChromeFrameMessageManager.loadFrameScript()` with the delayed-load flag set, the script gets loaded into every frame created from that point on. This is great, except that until Firefox 9, there was no way to stop loading the script, so it would keep happening even after your add-on was shut down.
Starting in Firefox 9, you should call the new `nsIChromeFrameMessageManager.removeDelayedFrameScript()` method to stop loading your script in newly-created frames. You do this like this, for example:
```js
browser.messageManager.removeDelayedFrameScript(
"chrome://myextension/content/somescript.js",
);
```
## Interface changes
- The `nsIURL` interface has been changed a bit. The `nsIURL.param` attribute was removed, and the `nsIURLParser.parsePath()` method has two fewer arguments than it did previously.
- Two methods have been removed from `nsIBrowserHistory`: `registerOpenPage()` and `unregisterOpenPage()`. These methods had been deprecated.
- The `nsIEditorSpellCheck.saveDefaultDictionary()` method has been removed as part of supporting per-site spell check settings. Also, `nsIEditorSpellCheck.updateCurrentDictionary()` no longer takes a parameter.
- The `nsIGlobalHistory3` interface has been removed. Its functionality was of limited (if any) use to add-ons, so this shouldn't affect anyone.
- Several specialized channels' properties attributes have been merged into the base `nsIChannel` interface. This shouldn't affect compatibility at all, since those interfaces inherit from `nsIChannel` anyway.
## Preference changes
The `geo.wifi.*` preferences no longer have default values, although they're honored if they exist. If your code reads these without handling the case where they don't exist, you need to update your code to handle the exception that gets thrown when they're not present.
## XPConnect changes
`nodePrincipal` and `baseURIObject` have been moved from `nsDOMClassInfo` to `XrayWrapper`. This shouldn't affect many add-ons, since it would only be an issue if they try to access these properties on DOM {{ domxref("Node") }} objects from unprivileged script that have requested XPConnect privileges using `enablePrivilege()`.
## DOM changes
- The long-obsolete method `Navigator.taintEnabled()` has been removed. This hasn't done anything useful in a very long time, but was often used in browser detection scripts, since it was Netscape-specific. Calling this method throws an exception starting in Firefox 9.
- Event handlers are now implemented as standard IDL interfaces. For most cases, this won't affect you, but [there are exceptions](/en-US/docs/Web/Events/Event_handlers#event_handler_changes_in_firefox_9).
## Other changes that may affect binary compatibility
These changes are notable in that they may affect binary XPCOM components. These will need rebuilding anyway, since that's required for every major release of Firefox, but could introduce compile-time errors, so they're worth noting in particular.
- The `nsIDOMHTMLDocument` interface now has a new `scripts` attribute, which implements the {{ domxref("Document.scripts") }} attribute.
- The `nsIJumpListShortcut.iconImageUri()` method has been added, to make it possible to establish favicons on jump list URI entries on Windows.
## Theme changes
The `pending` attribute has been added to the `<tab>` element. If this attribute is present, the tab is in the process of being restored by the session store service. You can use that to style the tab during the restore process. It's worth noting that if the user has turned on the "Don't load tabs until selected" preference, the `pending` attribute is set on tabs until they get loaded.
Similarly, tabs also now have an `unread` attribute; this property, if present, indicates that the tab has changed since the last time it was the active tab. You can use this to style tabs differently when they have changed since the last time the user looked at them. This is also present on tabs that have not yet been looked at during the current session.
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/67/index.md | ---
title: Firefox 67 for developers
slug: Mozilla/Firefox/Releases/67
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 67 that will affect developers. Firefox 67 was released on May 21, 2019.
## Changes for web developers
### Developer tools
- Debugger updates:
- [Column breakpoints](https://firefox-source-docs.mozilla.org/devtools-user/debugger/how_to/set_a_breakpoint/index.html) allow you to select the specific point (or column) in a line of code where you want the debugger to break ([Firefox bug 1528417](https://bugzil.la/1528417)).
- [Log points](https://firefox-source-docs.mozilla.org/devtools-user/debugger/set_a_logpoint/index.html) allow you to log specific information to the console during code execution without pausing execution and without the need to change the code.
- The [map scopes feature](https://firefox-source-docs.mozilla.org/devtools-user/debugger/using_the_debugger_map_scopes_feature/index.html) allows you to view the variables from the original source.
- You can [debug worker](/en-US/docs/Web/API/Web_Workers_API/Using_web_workers#debugging_worker_threads) threads directly in the debugger.
- [Web Console](https://firefox-source-docs.mozilla.org/devtools-user/web_console/index.html) updates:
- Navigate details in the console using the keyboard ([Firefox bug 1424159](https://bugzil.la/1424159)).
- Cmd + K will now clear the console of its contents on macOS ([Firefox bug 1532939](https://bugzil.la/1532939)).
- When the user clears the console, the error messages cache is cleared as well ([Firefox bug 717611](https://bugzil.la/717611)).
- The user can import existing modules into the current page using import ([Firefox bug 1517546](https://bugzil.la/1517546)).
- A new context menu item allows the user to use the **Copy Link Location** command ([Firefox bug 1457111](https://bugzil.la/1457111)).
- Clicking a link in the Console causes the same behavior that it would in a content window ([Firefox bug 1466040](https://bugzil.la/1466040)).
- Clicking the source link for a code file in the Console panel navigates to the Debugger if debugger knows the file ([Firefox bug 1447244](https://bugzil.la/1447244)).
- When the user has filtered the contents of the console, an icon will be added to the filter text box to clear the filter ([Firefox bug 1525821](https://bugzil.la/1525821)).
- [Network Monitor](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/index.html) enhancements:
- The [Header](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_details/index.html#headers) panel of the Network monitor will now display a notification for resources belonging to a known tracker ([Firefox bug 1485416](https://bugzil.la/1485416)).
- In the Network monitor [request columns](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_list/index.html#network-request-columns), you can control the visible columns and column sorting. The context menu now includes a command to restore the list sort parameters to the default ([Firefox bug 1454962](https://bugzil.la/1454962)).
- You can change the [width of the columns](https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_list/index.html#network-request-columns) in the Network Monitor to suit your workflow ([Firefox bug 1358414](https://bugzil.la/1358414)).
#### Removals
- The following Developer Tools panels have been removed (see [Deprecated tools](https://firefox-source-docs.mozilla.org/devtools-user/deprecated_tools/index.html) for details):
- Canvas debugger ([Firefox bug 1403938](https://bugzil.la/1403938)).
- Shader editor ([Firefox bug 1342237](https://bugzil.la/1342237)).
- WebAudio editor ([Firefox bug 1403944](https://bugzil.la/1403944)).
- The following Developer Tools have been deprecated (see [Deprecated tools](https://firefox-source-docs.mozilla.org/devtools-user/deprecated_tools/index.html) for details):
- WebIDE ([Firefox bug 1539462](https://bugzil.la/1539462)).
- Connect… page ([Firefox bug 1539462](https://bugzil.la/1539462)).
### HTML
- {{htmlelement("input")}} elements with `autocomplete="new-password"` set on them will no longer have previously saved passwords auto-filled ([Firefox bug 1119063](https://bugzil.la/1119063)).
### CSS
- The {{cssxref("revert")}} keyword has been implemented ([Firefox bug 1215878](https://bugzil.la/1215878)).
- The `break-word` value of the {{cssxref("word-break")}} property is now supported ([Firefox bug 1296042](https://bugzil.la/1296042)).
- The [`prefers-color-scheme`](/en-US/docs/Web/CSS/@media/prefers-color-scheme) media feature is now supported ([Firefox bug 1494034](https://bugzil.la/1494034)).
- Custom {{cssxref("cursor")}}s of greater than 32px in size are now disallowed, to mitigate potential malware uses of large cursors ([Firefox bug 1445844](https://bugzil.la/1445844)).
#### Removals
- Use of the proprietary `-moz-binding` property is now restricted to chrome and UA-stylesheets ([Firefox bug 1523712](https://bugzil.la/1523712)).
### SVG
_No changes._
### JavaScript
- {{jsxref("String.prototype.matchAll")}} has been implemented and enabled by default ([Firefox bug 1435829](https://bugzil.la/1435829), [Firefox bug 1531830](https://bugzil.la/1531830)).
- Support for the dynamic module {{jsxref("Statements/import", "import()", "#Dynamic_Imports")}} proposal is now available by default ([Firefox bug 1517546](https://bugzil.la/1517546)).
- The [hashbang grammar](/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#hashbang_comments) proposal is now implemented ([Firefox bug 1519097](https://bugzil.la/1519097)).
### APIs
#### DOM
- The default value for {{domxref("Response.statusText")}} is now `""` ([Firefox bug 1508996](https://bugzil.la/1508996)).
- User gestures are now preserved for rejected calls to {{domxref("Document.requestStorageAccess")}}, as well as fulfilled calls ([Firefox bug 1522912](https://bugzil.la/1522912)).
#### DOM events
- CSS transition ([Firefox bug 1530239](https://bugzil.la/1530239)) and animation ([Firefox bug 1531605](https://bugzil.la/1531605)) events now fire on disabled (e.g. form) elements.
- {{domxref("InputEvent.data")}} and {{domxref("InputEvent.dataTransfer")}} have been implemented ([Firefox bug 998941](https://bugzil.la/998941)).
- The `insertFromPasteAsQuotation` {{domxref("InputEvent.inputType")}} value is now supported ([Firefox bug 1532527](https://bugzil.la/1532527)).
#### Workers/Service workers
- Strict MIME type checks are now enforced on scripts imported by {{domxref("WorkerGlobalScope.importScripts()")}} ([Firefox bug 1514680](https://bugzil.la/1514680)).
#### Media, Web Audio, and WebRTC
- The [AV1 video codec](/en-US/docs/Web/Media/Formats/Video_codecs#av1) is now supported on Linux.
- [dav1d](https://code.videolan.org/videolan/dav1d) is now the default media decoder for [AV1](https://aomediacodec.github.io/av1-spec/av1-spec.pdf) (see for example [Firefox bug 1533742](https://bugzil.la/1533742) and [Firefox bug 1535038](https://bugzil.la/1535038)).
- Calling {{domxref("RTCPeerConnection.addTrack()")}} without specifying any streams to which to add the new track now works as expected: it adds a streamless track to the connection. Each peer is responsible for managing the association between the track and any stream on its end ([Firefox bug 1231414](https://bugzil.la/1231414)).
- The {{domxref("MediaDeviceInfo.groupId")}} property is now implemented ([Firefox bug 1213453](https://bugzil.la/1213453)). While it has existed in Firefox since Firefox 39, it did not actually gather related devices together into the same group IDs.
- The {{domxref("RTCIceCandidate.usernameFragment")}} property is now implemented ([Firefox bug 1490658](https://bugzil.la/1490658)).
- [WebVTT](/en-US/docs/Web/API/WebVTT_API) has been revised to correctly use `auto` as the default for the {{domxref("VTTCue")}} object's {{domxref("VTTCue.positionAlign", "positionAlign")}} property, instead of `center`. This causes the cue box's alignment to correspond to the alignment of the text within it ([Firefox bug 1528420](https://bugzil.la/1528420)).
#### Canvas and WebGL
- The [`EXT_float_blend`](/en-US/docs/Web/API/EXT_float_blend) WebGL extension has been enabled by default ([Firefox bug 1535808](https://bugzil.la/1535808)).
#### Removals
- The deprecated `ShadowRoot.getElementsByTagName`, `ShadowRoot.getElementsByTagNameNS`, and `ShadowRoot.getElementsByClassName` properties (part of Shadow DOM v0) have been removed ([Firefox bug 1535438](https://bugzil.la/1535438)).
- [`document.createEvent("TouchEvent")`](/en-US/docs/Web/API/Document/createEvent), {{domxref("document.createTouch()")}}, {{domxref("document.createTouchList()")}}, and the `ontouch*` event handler properties have been disabled on desktop to improve web compatibility on websites where touch support is used for mobile detection ([Firefox bug 1412485](https://bugzil.la/1412485)). In such cases, websites have been seen to behave incorrectly or unexpectedly on touchscreen laptops.
### Security
- [Notifications](/en-US/docs/Web/API/Notifications_API) are now only available in a [secure context](/en-US/docs/Web/Security/Secure_Contexts) ([Firefox bug 1429432](https://bugzil.la/1429432)).
- Firefox now blocks the loading of external protocol URLs in {{htmlelement("iframe")}}s ([Firefox bug 1527882](https://bugzil.la/1527882)).
### WebDriver conformance (Marionette)
#### API changes
- Made `WebDriver:SendAlertText` conformant to the [WebDriver specification](https://w3c.github.io/webdriver/) ([Firefox bug 1502360](https://bugzil.la/1502360)).
#### Bug fixes
- `WebDriver:NewWindow` will no longer timeout because inconsistencies across platforms regarding the `focus` event ([Firefox bug 1523234](https://bugzil.la/1523234)).
#### Others
- Both `WebDriver:ExecuteScript` and `WebDriver:ExecuteAsyncScript` now use `Promises` internally ([Firefox bug 1398095](https://bugzil.la/1398095)).
- `WebDriver:NewSession` returns Firefox's `BuildID` string as part of the capabilities object ([Firefox bug 1525829](https://bugzil.la/1525829)).
## Changes for add-on developers
### API changes
- Using the `proxy.settings.set()` method to change `{{WebExtAPIRef("types.BrowserSetting", "BrowserSetting")}}` values will throw an exception unless the extension was granted private window access by the user ([Firefox bug 1525447](https://bugzil.la/1525447)).
### Manifest changes
- A new manifest key, [incognito](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/incognito), defines the behavior of an extension in private browsing windows or tabs ([Firefox bug 1511636](https://bugzil.la/1511636)).
- The `toolbar_field_highlight` setting controls the background color used to indicate the current selection of text in the URL bar ([Firefox bug 1450114](https://bugzil.la/1450114)).
- The `toolbar_field_highlight_text` setting controls the text color used to indicate the current selection of text in the URL bar ([Firefox bug 1450114](https://bugzil.la/1450114)).
## See also
- Hacks release post: [Firefox 67: Dark Mode CSS, WebRender, and more](https://hacks.mozilla.org/2019/05/firefox-67-dark-mode-css-webrender/)
## Older versions
{{Firefox_for_developers(66)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/94/index.md | ---
title: Firefox 94 for developers
slug: Mozilla/Firefox/Releases/94
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 94 that will affect developers. Firefox 94 was released on November 2nd, 2021
## Changes for web developers
### HTML
No notable changes
### CSS
No notable changes
### JavaScript
No notable changes
### APIs
- The {{domxref("structuredClone()")}} global function is now supported for copying complex JavaScript objects ([Firefox bug 1722576](https://bugzil.la/1722576)).
#### DOM
- Developers can now provide a hint for the enter key label/icon used on virtual keyboards, using either [`HTMLElement.enterkeyhint`](/en-US/docs/Web/API/HTMLElement/enterKeyHint) or the global attribute [`enterkeyhint`](/en-US/docs/Web/HTML/Global_attributes/enterkeyhint) ([Firefox bug 1648332](https://bugzil.la/1648332)).
- The {{domxref("HTMLScriptElement.supports_static", "HTMLScriptElement.supports()")}} static method is now supported. This provides a simple and unified method for feature checking whether a browser supports particular types of scripts, such as JavaScript modules or classic scripts ([Firefox bug 1729239](https://bugzil.la/1729239)).
- The {{domxref("ShadowRoot.delegatesFocus")}} property is now supported, allowing code to check whether the `delegatesFocus` property was set when the [shadow DOM was attached](/en-US/docs/Web/API/Element/attachShadow) ([Firefox bug 1413836](https://bugzil.la/1413836)).
### WebDriver conformance (Marionette)
- `WebDriver:GetWindowHandle` and `WebDriver:GetWindowHandles` now return handles for browser windows instead of tabs, when chrome scope is enabled ([Firefox bug 1729291](https://bugzil.la/1729291))
### HTTP
- The `cache` directive of the [`Clear-Site-Data`](/en-US/docs/Web/HTTP/Headers/Clear-Site-Data) response header has been disabled by default.
It can be enabled using the preference `privacy.clearsitedata.cache.enabled` ([Firefox bug 1729291](https://bugzil.la/1729291)).
## Changes for add-on developers
- Support for `partitionKey`, the first-party URL of a cookie when it's in storage that is partitioned by top-level site, is added to {{WebExtAPIRef('cookies.get')}}, {{WebExtAPIRef('cookies.getAll')}}, {{WebExtAPIRef('cookies.set')}}, {{WebExtAPIRef('cookies.remove')}}, and {{WebExtAPIRef('cookies.cookie')}}. ([Firefox bug 1669716](https://bugzil.la/1669716))
- When a context menu is activated, {{WebExtAPIRef('menus.OnClickData','menus.OnClickData.srcUrl')}} returns the raw value of the `src` attribute of the clicked element, instead of the current URL (after redirects). ([Firefox bug 1659155](https://bugzil.la/1659155))
## Older versions
{{Firefox_for_developers(93)}}
| 0 |
data/mdn-content/files/en-us/mozilla/firefox/releases | data/mdn-content/files/en-us/mozilla/firefox/releases/99/index.md | ---
title: Firefox 99 for developers
slug: Mozilla/Firefox/Releases/99
page-type: firefox-release-notes
---
{{FirefoxSidebar}}
This article provides information about the changes in Firefox 99 that will affect developers. Firefox 99 was released on April 5, 2022.
## Changes for web developers
### HTML
No notable changes.
### CSS
No notable changes.
### JavaScript
No notable changes.
### APIs
- {{domxref("navigator.pdfViewerEnabled")}} is now enabled, and is the recommended way to determine whether a browser supports inline display of PDF files when navigating to them.
Sites that use the deprecated properties {{domxref("navigator.plugins")}} and {{domxref("navigator.mimeTypes")}} to infer PDF viewer support should now use the new property, even though these now return hard-coded mock values that match the signal provided by `pdfViewerEnabled` ([Firefox bug 1720353](https://bugzil.la/1720353)).
#### Media, WebRTC, and Web Audio
- The [`RTCPeerConnection.setConfiguration()`](/en-US/docs/Web/API/RTCPeerConnection/setConfiguration) method is now supported.
Among other things, this allows sites to adjust the configuration to changing network conditions ([Firefox bug 1253706](https://bugzil.la/1253706)).
#### Removals
- The [Network Information API](/en-US/docs/Web/API/Network_Information_API) was previously enabled on Android (only), but is now disabled by default on all platforms.
This API is on the path for removal because it exposes a significant amount of user information that might be used for fingerprinting.
([Firefox bug 1637922](https://bugzil.la/1637922)).
### WebDriver conformance (Marionette)
- Fixed a bug where the Shift key was not handled properly when part of a key sequence of the `WebDriver:ElementSendKeys` command ([Firefox bug 1757636](https://bugzil.la/1757636)).
## Changes for add-on developers
## Older versions
{{Firefox_for_developers(98)}}
| 0 |
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