var http_request = false;
function makePOSTRequest(url, parameters) {
   http_request = false;
   if (window.XMLHttpRequest) { // Mozilla, Safari,...
      http_request = new XMLHttpRequest();
      if (http_request.overrideMimeType) {
      	// set type accordingly to anticipated content type
         //http_request.overrideMimeType('text/xml');
         http_request.overrideMimeType('text/html');
      }
   } 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) {
      alert('Cannot create XMLHTTP instance');
      return false;
   }
   
   http_request.open('POST', url, true);
   http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
   http_request.setRequestHeader("Content-length", parameters.length);
   http_request.send(parameters);
}

function ping( tag )
{
	
	makePOSTRequest( "/ping.php", "tag=" + tag );
}

ping( window.location );