code: function() {
          var self = this,
              result = [];
          this.$tableBody.find('tr[class!="sum"]').each(function(index, tr) {
              if ($(tr).hasClass('selected')) {
                  result.push(self.rowSpan > 1 ? (index / self.rowSpan) : index);
              }
          });
          return result;
      }
docs: 获取选中行的序号
  @return {Array}
  @private