I need to increase a fraction in a text box
using javascript. 

the goal is to add 1 penny until it is 0.99
and then it will be 1.00 and 1.01

how can this be done in javascript?

this is what is not working.

```
var a;
a = document.getElementById('a1').value;
a = a+a;
alert(a);

```

alert returns

```
0.100.10

```

Additional Info

```
var a;
a = parseFloat(document.getElementById('b13').value);
a = a+a;
alert(a);

```

returns

```
0.2

```

i would rather see 0.20

but most importantly, how do increase this by 0.01 at a time ?

**SOLVED:**

both

```
var a;
a = parseFloat(document.getElementById('a1').value);
a = a+0.01;
alert(a);
}

```

and ...

```
document.getElementById('a1').value = +document.getElementById('a1').value + 0.01

```

worked fine.