// creates an XMLHttpRequest instance
function createXmlHttpRequestObject()
{
// will store the reference to the XMLHttpRequest object
var xmlHttp;
// this should work for all browsers except IE6 and older
try
{
// try to create XMLHttpRequest object
xmlHttp = new XMLHttpRequest();
}
catch(e)
{
// assume IE6 or older
var XmlHttpVersions = new Array('MSXML2.XMLHTTP.6.0',
'MSXML2.XMLHTTP.5.0',
'MSXML2.XMLHTTP.4.0',
'MSXML2.XMLHTTP.3.0',
'MSXML2.XMLHTTP',
'Microsoft.XMLHTTP');
// try every prog id until one works
for (var i=0; i<XmlHttpVersions.length && !xmlHttp; i++)
{
try
{
// try to create XMLHttpRequest object
xmlHttp = new ActiveXObject(XmlHttpVersions[i]);
}
catch (e) {} // ignore potential error
}
}
// return the created object or display an error message
if (!xmlHttp)
alert("Error creating the XMLHttpRequest object.");
else
return xmlHttp;
}

function createMsxml2DOMDocumentObject()
{
  // will store the reference to the MSXML object
  var msxml2DOM;
  // MSXML versions that can be used for our grid
  var msxml2DOMDocumentVersions = new Array("Msxml2.DOMDocument.6.0",
                                            "Msxml2.DOMDocument.5.0",
                                            "Msxml2.DOMDocument.4.0");
  // try to find a good MSXML object
  for (var i=0; i<msxml2DOMDocumentVersions.length && !msxml2DOM; i++)
  {
    try
    {
      // try to create an object
      msxml2DOM = new ActiveXObject(msxml2DOMDocumentVersions[i]);
    }
    catch (e) {}
  }
  // return the created object or display an error message
  if (!msxml2DOM)
    alert("Please upgrade your MSXML version from \n" +
          "http://msdn.microsoft.com/XML/XMLDownloads/default.aspx");
  else
    return msxml2DOM;
}