code: function new_handler(e, w, h) {
                  var elem = $(this),
                      data = $.data(this, str_data) || {};
  
                  // If called from the polling loop, w and h will be passed in as
                  // arguments. If called manually, via .trigger( 'resize' ) or .resize(),
                  // those values will need to be computed.
                  data.w = w !== undefined ? w : elem.width();
                  data.h = h !== undefined ? h : elem.height();
  
                  old_handler.apply(this, arguments);
              }
docs: The new_handler function is executed every time the event is triggered. This is used to update the internal element data store with the width and height when the event is triggered manually, to avoid double-firing of the event callback. See the "Double firing issue in jQuery 1.3.2" comments above for more information.