/***** creates an XMLHttpRequest instance *****/
function createXmlHttpRequestObject()
{
 var xmlHttp;
 try
 {
  xmlHttp = new XMLHttpRequest();
 }
 catch(e)
 {
  var XmlHttpVersions = new Array("MSXML2.XMLHTTP.6.0",
                                  "MSXML2.XMLHTTP.5.0",
                                  "MSXML2.XMLHTTP.4.0",
                                  "MSXML2.XMLHTTP.3.0",
                                  "MSXML2.XMLHTTP",
                                  "Microsoft.XMLHTTP");
  for (var i=0; i<XmlHttpVersions.length && !xmlHttp; i++)
  {
   try
   {
    xmlHttp = new ActiveXObject(XmlHttpVersions[i]);
   }
   catch (e) {}
  }
 }
 if (!xmlHttp)
 alert("Error creating the XMLHttpRequest object.");
 else
 return xmlHttp;
}