code: function normalizeEventName (eventName) {
              if (eventName.indexOf('on') !== 0) {
                  if (eventName[0] !== eventName[0].toUpperCase()) {
                      eventName = 'on' + eventName[0].toUpperCase() + eventName.substring(1);
                  }
                  else {
                      eventName = 'on' + eventName;
                  }
              }
              return eventName;
          }
docs: /*=========================
  Events/Callbacks/Plugins Emitter
  ===========================