code: function() {
              // 先复用default代码，然后重写
              this._super();
              
              var container = this.container,
                  options = this.options,
                  downWrap = this.downWrap;
              
              // 改写内容区域
              downWrap.innerHTML = '<div class="state-3d"><div class="drawer3d">' +
                                  '<div class="downwrap-content">' +
                                  '<p class="downwrap-progress"></p>' +
                                  '<p class="downwrap-tips">' +
                                  options.down.contentdown +
                                  ' </p></div>' +
                                  '<div class="drawer3d-mask"></div ></div></div>';
              
              // 由于直接继承的default，所以其实已经有default主题了，这里再加上本主题样式
              container.classList.add(CLASS_THEME);
  
              // 改写完后，对象需要重新查找
              this.downWrapProgress = downWrap.querySelector('.downwrap-progress');
              this.downWrapTips = downWrap.querySelector('.downwrap-tips');
              this.drawer = downWrap.querySelector('.drawer3d');
              this.drawerMask = downWrap.querySelector('.drawer3d-mask');
  
              // 留一个默认值，以免样式被覆盖，无法获取
              this.downWrapHeight = downWrap.offsetHeight || DEFAULT_DOWN_HEIGHT;
              // 由于downWrap被改变了，重新移动
              this._transformDownWrap(-this.downWrapHeight);
              this._resetDrawer();
          }
docs: 重写下拉刷新初始化，变为小程序自己的动画