Ajax request not retrieving xml output from webservice

Hello all,
 Ajax request not retrieving xml output from webservice
with following javascript functions

 
Function for processing xml and webservice

var xmlOut=null;
function ajaxRequest(url, repType, responseIn) {
    //alert(url)
    //document.getElementById('genMsg').innerHTML = 'Loading Contents Please wait....';
    //alert(url);
    try {
        req = new XMLHttpRequest(); /* e.g. Firefox */
    } catch(e) {
        try {
            req = new ActiveXObject("Msxml2.XMLHTTP");  /* some versions IE */
        } catch (e) {
            try {
        & ...