window.onload = function()
{
 ajaxresponse('http://granit-vt.ru/PreloadEngine.aspx');
 setInterval( function(){ ajaxresponse('http://granit-vt.ru/KeepAlive.aspx'); }, 720000);
}

function ajaxresponse(url)
{
 var http_request = false;
 if (window.XMLHttpRequest)
 { // Mozilla, Safari, ...
  http_request = new XMLHttpRequest();
  if (http_request.overrideMimeType)
  {
   http_request.overrideMimeType('text/xml');
  }
 }
 else if (window.ActiveXObject)
 { // IE
  try
  {
   http_request = new ActiveXObject("Msxml2.XMLHTTP");
  }
  catch (e)
  {
   try
   {
    http_request = new ActiveXObject("Microsoft.XMLHTTP");
   }
   catch (e)
   {

   }
  }
 }
 if (!http_request)
 {
  return false;
 }
 http_request.onreadystatechange = function()
 {
  if (http_request.readyState == 4)
  {
   if (http_request.status == 200)
   {

   }
   else
   {

   }
  }
 }
 http_request.open('GET', url, true);
 http_request.send(null);
}