Add css class to field if another is completed

[UNarmed]

Hey i am new to the site and i was wondering whether anyone could give me a hand here =] The title pretty much discribes the problem i am having. How would i go about adding a css class to field when another field is completed?

I need to get this done for validation purposes but so far i am totaly at a loss as to getting this right. Help would be greatly appreciated!

[harrierdh]

I think this is what you are asking. You reference the css class attribute like this in javascript.
<script>
document.getElementById( "divtwo" ).className = "newclass";
</script>
<div id="divtwo" class="oldclass" >&nbsp;</div>

[UNarmed]

Ok great thanks for the reply =]

How would i trigger this when someone enters text into a specific textfield though?

[harrierdh]

There are several events you can capture on any given html tag. Including onClick, onKeyPress, onBlur, onMouseOver etc.

The example below captures the onClick event in a button.

<script>
function changeClassName() {
document.getElementById( "divtwo" ).className = "newclass";
}
</script>
<div id="divtwo" class="oldclass" >&nbsp;</div>
<input type="button" id="mybutton" onClick="changeClassName()" />

[iDad]

Well done harrierdh.