Sending A Variable To A Js Function - Not Working

I've been fighting this one for a few months now, and it is causing me to have to create multiple functions that basically do the same thing. I am using the three functions below to replace text between two div tags on a page, based on a link that is clicked:

<td><a href="javascript:void(0)" onclick="htmlData('ajax/loginContent.php', 'view=1','data=2','displayField=txtResult')">Active Jobs</a></td>
";

Then further down the page:

<div id="txtResult">replace this content</div>

For some reason, I CANNOT send the div id name as a js variable. When I do it errors out. BUT if I replace displayField in the js functions below with "txtResult" it works fine.

function GetXmlHttpObject(handler) {
var objXMLHttp=null
if (window.XMLHttpRequest)
{

[Code].....