code: function getY(event) {
    let originalEvent = event.originalEvent;
    let touches = originalEvent? originalEvent.changedTouches : event.changedTouches;
    let touch = touches && touches[0];
  
    if (touch) {
      return touch.screenY;
    } else {
      return event.clientY;
    }
  }
docs: Gets the y offset for a given event.
  Work for touch and mouse events.
  @method getY
  @return {Number}
  @private