---
title: Opera 20 released
authors:
- mathias-bynens
intro: '[Opera 20 for Mac and Windows](http://www.opera.com/computer) (based on Chromium 33) is out! Here’s what that means for web developers.'
tags:
- extensions
- javascript
- odin
- opera-20
layout: post
---

[Opera 20 for Mac and Windows](http://www.opera.com/computer) (based on Chromium 33) is out! Here’s what that means for web developers.

## `requestAutoComplete()`

`<form>` elements now support a new method named `requestAutocomplete`, which can be used to ask the browser to populate the form. The browser displays a dialog to the user asking for permission and allowing the user to select which details they’d like to provide. This greatly speeds up filling out address or payment details. For more details, see [the HTML5 Rocks tutorial on `requestAutoComplete()`](http://www.html5rocks.com/en/tutorials/forms/requestautocomplete/).

## Custom Elements

Opera 20 supports the Web Components / Custom Elements spec by default. This means you can use [`document.registerElement()`](http://w3c.github.io/webcomponents/spec/custom/#extensions-to-document-interface-to-register) to register custom elements, and `document.createElement(elementName, typeExtension)` to instantiate type extension-style custom elements. See [this Custom Elements tutorial](http://www.html5rocks.com/en/tutorials/webcomponents/customelements/) for more information.

## Unprefixed Page Visibility API

You can now use  `document.hidden` instead of `document.webkitHidden` and listen for `visibilitychange` event rather than the `webkitvisibilitychange` event.

## More extension APIs

Opera 20 for Desktop adds the following APIs to extensions:

* [`chrome.system.storage`](http://dev.opera.com/extension-docs/system.storage.html)
* [`chrome.downloads`](http://dev.opera.com/extension-docs/downloads.html)
* [`chrome.proxy`](http://dev.opera.com/extension-docs/proxy.html)

See [our Opera 15+ extensions documentation](http://dev.opera.com/extension-docs/) for in-depth discussion of these APIs.

If you’re interested in experimenting with features that are in the pipeline for future versions of Opera, we recommend following [our Opera Developer stream](http://www.opera.com/developer).

Add post titled “Opera 20 released”
Add post titled “Opera 20 released”
