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$.extend({
          initializeUiBlocking: function () {
              if (typeof ($.blockUI) != 'undefined') {
                  $.blockUI.defaults.css = { border: 'none', backgroundColor: 'transparent' }
                  $.blockUI.defaults.message = '<img src="Images/ajax-loader.gif" />';
 
                  var request = Sys.WebForms.PageRequestManager.getInstance();
                  request.add_initializeRequest(function (sender, args) {
                      request.get_isInAsyncPostBack() && args.set_cancel(true);
                  });
                  request.add_beginRequest(function () { $.blockUI(); });
                  request.add_endRequest(function () { $.unblockUI(); });
              }
          }
      });
 
      $(document).ready(function () {
          $.initializeUiBlocking();
      });