form submit behaviour in IE5.5/IE5.0 is different

[dheeraja]

I am clueless as to why this is happeneing and how to correct it.
Here is what is happening.

In my jsp, lets say Page1.jsp I have alot of hidden parameters and other elements in the form.
On clicking a link, I submit the form to a servlet and then change the url of the page to point to another servlet.
The JavaScriptcode being:

function changeTab(tabNumber){
document.mainform.submit(); --->send to Servlet 1
// replace the url with the different tabNumber
var newURL =unescape(document.location.href);
newURL=replaceURL(newURL,tabNumber);
window.location.href=newURL; --->send to Servlet 2
}

In Servlet 2,
I have code similar to the following:
String name = request.getParameter("report_date"

where "report_date" was a hidden parameter in Page1.jsp e.g.
<input type=&quot;hidden&quot; nam,e=&quot;report_date&quot; value=&quot;2002/07/29&quot;>

Now comes the interesting part
in IE5.0 and IE4.0
name = &quot;2002/07/29&quot;;
but in IE5.5
name = null

Can anyone please tell me why this different behaviour of how to correct it?
Thanks in advance.