function getXmlHttpObject()
{
  if (window.XMLHttpRequest) // code for IE7+, Firefox, Chrome, Opera, Safari
  {
    return new XMLHttpRequest();
  }
  else if (window.ActiveXObject) // code for IE6, IE5
  {
    return new ActiveXObject("Microsoft.XMLHTTP");
  }
  else
  {
    alert("Warning! Your browser does not support AJAX.");

    return null;
  }
}