js获取元素距离顶部的高度

  mounted() {
    let that = this;
    // this.dom = this.$refs.multipleTable.bodyWrapper;
    // this.dom.addEventListener("scroll", () => {
    //   this.$nextTick(() => {
    //   });
    // });

    document.onkeydown = function (e) {
      if (e.code == "Tab" && that.$refs.multipleTable) {
        that.scrollTabSure = true;
        setTimeout(() => {
          that.scrollTabSure = false;
        }, 300);
      }
    };
  },
  methods: {
    setScrollTopStart() {
      let topObj = {};
      for (let i = 0; i < this.tableData.length; i++) {
        let elIdNew = document.getElementById("scoreInput" + i);
        if (elIdNew) {
          console.log(elIdNew);
          topObj[`scoreInput${i}`] = elIdNew.getBoundingClientRect().top;
        }
      }
      this.topObj = topObj;
      console.log(topObj);
    },
    getNowElFn(index) {
      const elId = document.getElementById("scoreInput" + index);
      let topNum = Number(elId.getBoundingClientRect().top);
      let endNum = this.topObj[`scoreInput${index}`] - 826;
      console.log(endNum);
      if (!this.scrollTabSure) {
        return;
      }
      this.scrollTabSure = false;

      // const dom = this.$refs[`scoreInput${index}`].$el;
      // console.log(this.$refs[`scoreInput${index}`]);
      // console.log(dom.offsetHeight, "offsetHeight");
      // console.log(dom.offsetWidth, "offsetWidth");
      // console.log(dom.offsetLeft, "offsetLeft");
      // console.log(dom.offsetTop, "offsetTop");
      // console.log(dom.scrollTop, "scrollTop");

      if (endNum > 0) {
        this.saveScroll(endNum);
      } else {
        this.saveScroll(0);
      }
    },
    saveScroll(endNum) {
      this.$nextTick(() => {
        setTimeout(() => {
          var scrollTop = this.$el.querySelector(".el-table__body-wrapper");
          scrollTop.scrollTop = endNum;
        }, 13);
      });
    },