<tr class="step-jump"></tr>
<tr class="step-jump"></tr>
<div style="position:fixed;top:25%;right:0;">
          <el-steps
            direction="vertical"
            finish-status="wait"
            space="50px"
            :active="activeStep">
            <el-step
              v-for="(item, index) in stepsArr"
              :key="index"
              :title="item.title"
              @click.native="jump(index)">
            </el-step>
          </el-steps>
 </div>
js:
data() {
    return {
      activeStep: 0,
      scrollTop: 0, // 没用到
      stepsArr: [
        { title: '一般状况' },
        { title: '生活方式' },
        { title: '脏器功能' },
        { title: '查体' },
        { title: '辅助检查' },
        { title: '现存主要健康问题' },
        { title: '住院治疗情况' },
        { title: '主要用药情况' },
        { title: '非免疫规划预防接种史' },
        { title: '健康评价' },
        { title: '健康指导' }
      ]
    }
  },
mounted() {
    this.$nextTick(function() {
      window.addEventListener('scroll', this.onScroll)
    })
  },
methods:{
  // 当元素滚动条被滚动时运行的脚本
    onScroll() {
      // var box = document.getElementById('box')
      // var t = document.documentElement.scrollTop || document.body.scrollTop
      // box.style.top = t + 'px'

      var jump = document.querySelectorAll('.step-jump')
      var distance =
        document.documentElement.scrollTop ||
        window.pageYOffset ||
        document.body.scrollTop
      jump.forEach((item, index) => {
        if (distance >= item.offsetTop) {
          this.activeStep = index
        }
      })
    },
    // 锚点点击
    jump(index) {
      console.log(index)
      this.activeStep = index
      // 用 class=".step-jump" 添加锚点，此时的类名要放在tr上，放在td上不对，
      // 以后做的时候要注意这点，不是表格的时候，如何放置锚点
      let jump = document.querySelectorAll('.step-jump')
      // 通过 offsetTop 获取对象到窗体顶部的距离，然后赋值给 scrollTop，就能实现锚点的功能
      let total = jump[index].offsetTop
      console.log(total)
      // scrollTop滚动条距离页面的距离
      let distance =
        document.documentElement.scrollTop ||
        window.pageYOffset ||
        document.body.scrollTop
      // console.log(distance)
      // 平滑滚动，时长500ms，每10ms一跳，共50跳
      let step = total / 50
      if (total > distance) {
        smoothDown()
      } else {
        let newTotal = distance - total
        step = newTotal / 50
        smoothUp()
      }
      function smoothDown() {
        if (distance < total) {
          distance += step
          document.body.scrollTop = distance
          document.documentElement.scrollTop = distance
          window.pageYOffset = distance
          setTimeout(smoothDown, 10)
        } else {
          document.body.scrollTop = total
          document.documentElement.scrollTop = total
          window.pageYOffset = total
        }
      }
      function smoothUp() {
        if (distance > total) {
          distance -= step
          document.body.scrollTop = distance
          document.documentElement.scrollTop = distance
          window.pageYOffset = distance
          setTimeout(smoothUp, 10)
        } else {
          document.body.scrollTop = total
          document.documentElement.scrollTop = total
          window.pageYOffset = total
        }
      }
    }
}