//<![CDATA[
    Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
    function EndRequestHandler(sender, args)
    {
       if (args.get_error() != undefined)
       {
           if ((args.get_response().get_statusCode() == '12007') || (args.get_response().get_statusCode() == '12029'))
           {
            //Show a Message like 'Please make sure you are connected to internet';
            //alert('Please make sure you are connected to internet');
            args.set_errorHandled(true); 
           }
       }
    }
 //]]>