Javascript code that works in Firefox but not in IE

[knkk]

I have a link called "Save" on a page of mine, which, when clicked on (the url is typically like this)

javascript:savesubmit('form31','results31','1','movies','178')

, calls a javascript function called "savesubmit", which in turn calls a script using AJAX (the script URL is http://www.mysite.com/section/myspace/save.php).

This is the JavaScript function savesubmit:

function savesubmit(formname, loc, noofvenues, which, mapid)
{
	var f = document.forms[formname];
             alert(f);//this alert was to test if the form name was coming in properly
	var params = "";
	for (i=0;i < (f.elements.length);i++) {
		params = params + f.elements[i].name +'='+ encodeURI(f.elements[i].value) + '&'; 
	}

	shows = loc;
	xmlHttp=GetXmlHttpObject();
	
	if (xmlHttp==null)
	{
		alert ("Browser does not support HTTP Request");
		return;
	}
	var url = 'http://www.mysite.com/section/myspace/save.php/'+which+'/'+f.eventid.value+'/1/'+mapid+'/'+noofvenues
	var eventid = f.eventid.value;
	url = url + "?" + params;
	var update_loc = eventid + 'save';
	var update_form = eventid;
	xmlHttp.onreadystatechange=stateChangedALL;
	xmlHttp.open("GET",url,true);
	xmlHttp.send(null);
	updatesave(update_form, update_loc, noofvenues, which, mapid);
}

The form is in a div tag with id 'form31', and the result will be sent to a div tag with id 'results31'.

The problem is, this thing is working in IE but not in FF. When I click on the Save link, it says "'elements.length' is null or not an object". And the alert I put for testing says [object] instead of giving the form name (both in IE and in FF).

Here is the <td> which has the forms etc.

<TD WIDTH="510" BGCOLOR="#FFFFFF" VALIGN="TOP" STYLE='padding-right: 10'>
	<A HREF="/profile/movies/31"><SPAN CLASS="Basic_LARGE_BLUE_LINK">Cheeni Kum</SPAN></A> 
	<BR>
             <SPAN CLASS="Basic_LARGE_NORMAL">64-year-old Buddhadeb is single and lives with mom. Now, aren't the possibilities endless?</SPAN>
	<BR>
             <BR><A HREF='/profile/locations/178'>PVR Cinema (Punjagutta)</A> (13.3 km)
	<BR><BR>
	<DIV id="31save" STYLE="float:left">
		<A HREF="/profile/movies/31/1">Rate</A> • 
		<A HREF="javascript:savesubmit('form31','results31','1','movies','178')">Save</A> • 
		<A HREF="/profile/locations/178/4">Map</A>							<DIV STYLE="clear:both;"></DIV>
	</DIV>

	<FORM NAME="deleteform31" STYLE="margin:0px">
		<INPUT TYPE="hidden" NAME="eventid" VALUE="31">
		<INPUT TYPE="hidden" NAME="edittype" VALUE="delete">
	</FORM>
	<FORM NAME="form31" STYLE="margin:0px">
		<INPUT TYPE="hidden" NAME="eventid" VALUE="31">
		<INPUT TYPE="hidden" NAME="edittype" VALUE="update">
	</FORM>
	<DIV STYLE="clear:both"></DIV>
	<DIV id="results31" ></DIV>
</TD>

Can someone kindly help? Thank you for your time!