code: function(selectedIndex, fire) {
          var curTab, curContent;
          if (typeof selectedIndex != 'undefined') {
              this.$tabs.removeClass('active');
              this.$contents.hide();
  
              this.options.selectedIndex = selectedIndex;
              curTab = $(this.$tabs[selectedIndex]).addClass('active');
              curContent = $(this.$contents[selectedIndex]).show();
  
              if (fire === undefined || !!fire) {
                  /**
                   * 切换 tab
                   * @event Tab#change
                   * @param {Object} e            事件对象
                   * @param {Object} data         数据
                   * @param {Number} data.index   序号
                   * @param {String} data.title   tab 标题
                   * @param {String} data.content tab 内容
                   */
                  curTab.trigger('change', {
                      index: selectedIndex,
                      title: curTab.text(),
                      content: curContent.html()
                  });
              }
          } else {
              var curIndex = this.options.selectedIndex;
              curTab = $(this.$tabs[curIndex]);
              curContent = $(this.$contents[curIndex]);
              return {
                  index: curIndex,
                  title: curTab.text(),
                  content: curContent.html()
              };
          }
      }
docs: 获取/设置当前被选中的 tab
  @param {Number}  [selectedIndex] 序号
  @param {Boolean} [fire]          触发 change 事件，默认 true
  @fires Tab#change
  @return {Object}