function pingclick(url)
{
   var xmlhttp;

   if (window.XMLHttpRequest)
   {
     // code for IE7+, Firefox, Chrome, Opera, Safari
     xmlhttp = new XMLHttpRequest();
   }
   else
   {
      if (window.ActiveXObject)
      {
         // code for IE6, IE5
         xmlhttp = new ActiveXObject('Microsoft.XMLHTTP');
      }
      else
      {
         return true;
      }
   }

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