var xmlHttp = createXmlHttpRequestObject();

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;
  }
}

function handleRequestStateChange()
{
  if (xmlHttp.readyState == 4)
  {
    if (xmlHttp.status == 200)
    {
      try
      {
        handleServerResponse();
      }
      catch(e)
      {
        alert("Error reading the response: " + e.toString());
      }
    }
    else
    {
      alert("There was a problem retrieving the data:\n" +
            xmlHttp.statusText);
    }
  }
}

function handleServerResponse()
{
  var xmlResponse = xmlHttp.responseXML;
  if (!xmlResponse || !xmlResponse.documentElement)
    throw("Invalid XML structure:\n" + xmlHttp.responseText);
  var rootNodeName = xmlResponse.documentElement.nodeName;
  if (rootNodeName == "parsererror")
    throw("Invalid XML structure:\n" + xmlHttp.responseText);
  xmlRoot = xmlResponse.documentElement;

  if (rootNodeName != "response" || !xmlRoot.firstChild)
    throw("Invalid XML structure:\n" + xmlHttp.responseText);

  responseText = xmlRoot.firstChild.data;

  if(responseText == undefined){
    myDiv.innerHTML = xmlHttp.responseText;
  } else {
    myDiv.innerHTML = responseText;
  }

}