function XCreateXmlHTTPRequest()
{
 try {
   if (typeof ActiveXObject != 'undefined')
     return new ActiveXObject('Microsoft.XMLHTTP');
   else
   if (window["XMLHttpRequest"])
     return new XMLHttpRequest();
 }
 catch (e) {
   changeStatus(e);
 }
 return null;
}


function XDownloadUrl(url, callback, errcallback)
{
 var status = -1;
 var request = XCreateXmlHTTPRequest();
 if (!request)
   return false;

 request.onreadystatechange = function()
 {
   if (request.readyState == 4)
   {
     try {
       status = request.status;
     }
     catch (e) {
       // Usually indicates request timed out in FF.
     }
     if (status == 200)
     {
       callback(request.responseText, request.status);
       request.onreadystatechange = function() {};
     }
     else
     if (typeof(errcallback) == "function")
      errcallback(status);
   }
 }

 request.open('GET', url, true);
 try {
   request.send(null);
 }
 catch (e) {
   changeStatus(e);
 }
}