code: function(_event, _selector, _handler){
              _selector = $._cleanSelector(_selector);
              return this._$forEach(function(_node){
                  var _uid = $._$uid(_node);
                  var _handlers, _events, _selectors;
                  if (!(_handlers = $._delegateHandlers[_uid]) ||
                      !(_events = _handlers[_event]) || !(_selectors = _events[_selector])){
                      return;
                  }
                  for(var _len = _selectors.length;_len--;){
                      var _fn = _selectors[_len];
                      //如果没有传入_handler或者 函数匹配了
                      if(!_handler || _fn._raw === _handler){
                          _v._$delEvent(_node, _event, _fn);
                          _selectors.splice(_len,1);
                      }
                  }
                  // 如果被删光了
                  if(!_selectors.length) delete _events[_selector];
              });
              return this;
          }
docs: 私有方法 解绑事件代理