Resize problemm

I have a problem when i resize the ie or change the resolution.
In firefox works perfect but in ie not.
I have a div and a ajax function that loads the content in div like
mainarea is the div.
The problem is when i resize ie the div content goest down, about 800px
from top.
If someone can help me. I can give a link of the app. Thanks

document.getElementById(‘mainArea’).style.display = “block”;
new Ajax.Updater(‘mainArea’, window,{method:‘get’, asynchronous:true,