code: function _addEventListener() {
      _isAnimating = true;
      // If transition is not supported, call handler directly (IE9/OperaMini).
      if ( _transitionEndEvent ) {
        _dom.addEventListener( _transitionEndEvent,
                               _transitionCompleteBinded );
        this.trigger( BaseTransition.BEGIN_EVENT, { target: this } );
      } else {
        this.trigger( BaseTransition.BEGIN_EVENT, { target: this } );
        _transitionCompleteBinded();
      }
    }
docs: Add an event listener to the transition, or call the transition
  complete handler immediately if transition not supported.