code: function computeStripX() {
        if (this.hideHorizontal) {
          // 没有开启横向滚动条
          return;
        }
        var clientEle = this.$refs['happy-scroll'];
        var slotEle = this.$slots.default[0]['elm'];
        this.$refs.stripX.computeStrip(slotEle.scrollWidth, clientEle.clientWidth);
      }
docs: 计算横向滚动条宽度度与元素宽度百分比