function GetXmlHttpObject(handler)
{ 
   var objXmlHttp = null

   if (navigator.userAgent.indexOf("Opera")>=0)
   {
      alert("Please use Internet Explorer or Firefox.") ;
      return;
   }
   
   if( navigator.userAgent.indexOf("MSIE") >= 0 )
   { 
      var strName="Msxml2.XMLHTTP";
      if( navigator.appVersion.indexOf( "MSIE 5.5" ) >=0 )
      {
         strName="Microsoft.XMLHTTP";
      } 
      try
      { 
         objXmlHttp = new ActiveXObject(strName);
         objXmlHttp.onreadystatechange = handler;
         return objXmlHttp;
      } 
      catch(e)
      { 
         alert("Error. Scripting for ActiveX might be disabled") ;
         return;
      } 
   } 
   if( navigator.userAgent.indexOf( "Mozilla" ) >=0 )
   {
      objXmlHttp = new XMLHttpRequest();
      objXmlHttp.onload = handler;
      objXmlHttp.onerror = handler;
      return objXmlHttp;
   }
}