//  register for our events
            Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(beginRequest);
            Sys.WebForms.PageRequestManager.getInstance().add_endRequest(endRequest);

            function beginRequest(sender, args) {
                // show the popup
                $find('mdlProgress').show();
            }

            function endRequest(sender, args) {
                //  hide the popup
                $find('mdlProgress').hide();
            }