vue中获取DOM高度，通过ref。如下：

   /**
     * @description 计算表格高度
     */
    setTabelHeight() {
      this.$nextTick(() => {
        let supPX = 1;
        let containerHeight =
          this.$refs.containerRef.offsetHeight -
          this.getDomStyle(this.$refs.containerRef, "paddingTop") -
          this.getDomStyle(this.$refs.containerRef, "paddingBottom");
        let headerHeight = this.$refs.headerRef.$el.offsetHeight;
        let searchHeight =
          this.$refs.searchRef.$el.offsetHeight +
          this.getDomStyle(this.$refs.searchRef.$el, "marginTop");
        let searchBtnHeight =
          this.$refs.searchBtnRef.$el.offsetHeight +
          this.getDomStyle(this.$refs.searchBtnRef.$el, "marginTop");
        let addBtnHeight =
          this.$refs.addBtnRef.$el.offsetHeight +
          this.getDomStyle(this.$refs.addBtnRef.$el, "marginTop");
        let paginHeight =
          this.$refs.paginRef.$el.offsetHeight +
          this.getDomStyle(this.$refs.paginRef.$el, "marginTop");
        this.tableMaxHeight =
          containerHeight -
          headerHeight -
          searchHeight -
          searchBtnHeight -
          addBtnHeight -
          paginHeight -
          this.getDomStyle(this.$refs.tableRef.$el, "marginTop") -
          supPX;
      });
    },
    /**
     * @description 获取元素样式
     * @param {Node} dom dom元素
     * @param {String} attr 元素属性
     */
    getDomStyle(dom, attr) {
      var computedStyle = getComputedStyle(dom, null);
      return Number(computedStyle[attr].replace("px", ""));
    },

uni-app 动态获取元素高度 如下：

需要通过官方的一个调用方法。

<view :class="{'sucktheTop':true,'sticky-fixed':isF}">

	mounted() {
			let _this = this;
			uni.getSystemInfo({
				success: function(res) { // res - 各种参数
					console.log(res.windowWidth); // 屏幕的宽度 

					let info = uni.createSelectorQuery().select(".sucktheTop");
					info.boundingClientRect(function(data) { //data - 各种参数
						console.log(data) // 获取元素宽度
						_this.domHeight = data.height;
					}).exec()
				}
			});
		},