code: function (evt) {
              if(this.fireEvent('before' + evt.type.replace(/^on/, '').toLowerCase()) === false){
                  return false;
              }
              if(this.fireEvent(evt.type.replace(/^on/, ''), evt) === false){
                  return false;
              }
              return this.fireEvent('after' + evt.type.replace(/^on/, '').toLowerCase())
          }
docs: 触发事件代理
  @method _proxyDomEvent
  @private
  @return { * } fireEvent的返回值
  @see UE.EventBase:fireEvent(String)