[eluser]kgill[/eluser]
For future reference if you ask questions involving browser problems you need to also identify what browser version you're referring to, IE6, IE7 and IE8 all have very different issues when it comes to javascript. It also looks like you're using jQuery (you should also mention that) so I'm going to base my answer off that.
If I had to guess I'd say it's your document.getElementById that's screwing things up. Why aren't you using jQuery's selectors to get and set data instead?