docs: function mousedown_callback(e) {
                  mouse_down_time = new Date().getTime();
                  var context = $(this);
  
                  // set a timeout to call the longpress callback when time elapses
                  timeout = setTimeout(function() {
                      if (typeof longCallback === "function") {
                          longCallback.call(context, e);
                      } else {
                          $.error('Callback required for long press. You provided: ' + typeof longCallback);
                      }
                  }, duration);
              }