code: function(_index){
              if(!this.__transition[_index])
                  return '';
              var _rule = this.__transition[_index],
                  _t = _rule.duration + _rule.delay;
              if( _t > this.__sumtime){
                  this.__lastProp = {};
                  this.__sumtime = _t;
                  this.__lastProp[_rule.property] = _rule.property;
              }else if(_t == this.__sumtime){
                  this.__lastProp[_rule.property] = _rule.property;
              }
              return _rule.property + ' ' + _rule.duration + 's ' + _rule.timing + ' ' + _rule.delay + 's,';
          }
docs: 解析动画的规则