function onRadAjaxManagerRequestStarted(ajaxManager, eventArgs)
 {
   var re = new RegExp("oHyperlink|oUpload|oDownload|oExport", "ig");
   if (eventArgs.EventTarget.match(re))
    {
       eventArgs.EnableAjax = false;
       //alert( 'Postback request has just started: ' + eventArgs.EventTarget);
    }
   else
    {
       //alert( 'AJAX request has just started: ' + eventArgs.EventTarget);
    } 
 }

 function onRadAjaxManagerRequestStartedInfo(ajaxManager, eventArgs)
 {
   if (eventArgs.EnableAjax == false)
    {
       //alert( 'Postback request has just started: ' + eventArgs.EventTarget);
    }
   else
    {
       //alert( 'AJAX request has just started: ' + eventArgs.EventTarget);
    } 
 }