vue3 锚点定位 点击滚动高亮

功能描述

点击导航跳到对应模块的起始位置，并且高亮点击的导航；
滚动到相应的模块时，对应的导航也自动高亮；

效果展示

注意事项

1. 一定要明确哪个是要滚动的盒子；
2. 滚动的高度要减去导航栏的高度；
3. 当前在导航1，点击导航4时，会出现导航2、导航3和导航4依次高亮的现象，定义变量判断当前为点击时不监听滚动事件即可；
   isScroll.value = false

核心代码

onMounted(() => {
  nextTick(() => {
  	// 监听滚动的盒子的滚动事件
    document.getElementById('scrollBox').addEventListener("scroll", onScroll);
  })
})

onBeforeUnmount(() => {
  document.getElementById('scrollBox').removeEventListener('scroll', onScroll)
})


const scrollToAnchor = (id, index) => {
 activeIndex.value = index
  var anchor = document.getElementById(id);
  var scrollBox = document.getElementById('scrollBox')
  nextTick(() => {
    scrollBox.scrollTo({
      top: anchor.offsetTop - 30,
      behavior: 'smooth'
    });
 })
  isScroll.value = false
   // 点击时暂停页面的滚动监听事件，防止点击时导航高亮出现走马灯效果；
  // 此处的定时器存在缺陷，点击完2秒之内滚动还是会偶现走马灯现象；
  let timeId = '';
  clearTimeout(timeId);
  timeId = setTimeout(() => {
    isScroll.value = true;
  }, 2000);
};


// 滚动监听器
const onScroll = ()=> {
  if(!isScroll.value) return
  // 获取所有锚点元素
  const navContents = document.querySelectorAll('.container .section')
  // 所有锚点元素的 offsetTop
  const offsetTopArr = []
  navContents.forEach(item => {
    offsetTopArr.push(item.offsetTop-30)
  })
  // 获取当前文档流的 scrollTop
  const scrollTop = document.getElementById('scrollBox').scrollTop
  // 定义当前点亮的导航下标
  let navIndex = 1
  for (let n = 1; n <= offsetTopArr.length; n++) {
    // 如果 scrollTop 大于等于第 n 个元素的 offsetTop 则说明 n-1 的内容已经完全不可见
    // 那么此时导航索引就应该是 n 了
    if (scrollTop >= offsetTopArr[n-1]) {
      navIndex = n
    }
  }
  // 把下标赋值给 vue 的 data
  activeIndex.value = navIndex
}

完整代码

<template>
  <div class="box" id="scrollBox" v-loading="loading">
    <div class="fixed-box">
      <div v-for="(i) in defaultTabs" :class="{active_anchor: activeIndex === i}">
          <a @click="scrollToAnchor(`section${i}`, i)">
            <span v-if="i == 1">导航1</span>
            <span v-if="i == 2">导航2</span>
            <span v-if="i == 3">导航3</span>
            <span v-if="i == 4">导航4</span>
            <span v-if="i == 5">导航5</span>
          </a>
        </div>
    </div>
    <div class="container" id="printcontent">
      <div class="section" id="section1">
        <h3>日历</h3>
        <el-calendar v-model="value" />
      </div>
      <div class="section" id="section2">
        <h3>带边框列表</h3>
        <el-descriptions class="margin-top" title="" :column="4" border>
          <template v-for="i in 4">
            <el-descriptions-item label="Username">kooriookami</el-descriptions-item>
            <el-descriptions-item label="Telephone">18100000000</el-descriptions-item>
            <el-descriptions-item label="Place" :span="2">Suzhou</el-descriptions-item>
            <el-descriptions-item label="Remarks">123123</el-descriptions-item>
            <el-descriptions-item label="Username">一一一</el-descriptions-item>
            <el-descriptions-item label="Remarks">123123</el-descriptions-item>
            <el-descriptions-item label="Remarks">-</el-descriptions-item>
            <el-descriptions-item label="Remarks">-</el-descriptions-item>
            <el-descriptions-item label="Remarks">-</el-descriptions-item>
          </template>
        </el-descriptions>
      </div>
      <div class="section" id="section3">
        <h3>普通表格</h3>
        <el-table :data="tableData" style="width: 100%">
          <el-table-column prop="date" label="Date" width="180" />
          <el-table-column prop="name" label="Name" width="180" />
          <el-table-column prop="address" label="Address" />
        </el-table>
      </div>
      <div class="section" id="section4">
        <h3>普通卡片</h3>
        <el-card class="box-card">
          <template #header>
            <div class="card-header">
              <span>Card name</span>
              <el-button class="button" text>Operation button</el-button>
            </div>
          </template>
          <div v-for="o in 10" :key="o" class="text item">{{ 'List item ' + o }}</div>
          <template #footer>Footer content</template>
        </el-card>
      </div>
    </div>
  </div>
</template>

<script setup>
import { onMounted, ref, nextTick, onBeforeUnmount } from 'vue'
const loading = ref(false)
const value = ref(new Date())
const defaultTabs = ref([1, 2, 3, 4, 5])
const activeIndex = ref(1)
const isScroll = ref(true) // 点击导航栏时，暂时停止监听页面滚动
const tableData = [
  {
    date: '2016-05-03',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
  {
    date: '2016-05-02',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
  {
    date: '2016-05-04',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
  {
    date: '2016-05-01',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
  {
    date: '2016-05-04',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
  {
    date: '2016-05-01',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
  {
    date: '2016-05-04',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
  {
    date: '2016-05-01',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
  {
    date: '2016-05-04',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
  {
    date: '2016-05-01',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
  {
    date: '2016-05-04',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
  {
    date: '2016-05-01',
    name: 'Tom',
    address: 'No. 189, Grove St, Los Angeles',
  },
]

onMounted(() => {
  nextTick(() => {
    document.getElementById('scrollBox').addEventListener("scroll", onScroll);
  })
})

onBeforeUnmount(() => {
  document.getElementById('scrollBox').removeEventListener('scroll', onScroll)
})

const scrollToAnchor = (id, index) => {
 activeIndex.value = index
  var anchor = document.getElementById(id);
  var scrollBox = document.getElementById('scrollBox')
  nextTick(() => {
    scrollBox.scrollTo({
      top: anchor.offsetTop - 30,
      behavior: 'smooth'
    });
 })
  // 点击时暂停页面的滚动监听事件，防止点击时导航高亮出现走马灯效果；
  // 此处的定时器存在缺陷，点击完2秒之内滚动还是会偶现走马灯现象；
  isScroll.value = false
  let timeId = '';
  clearTimeout(timeId);
  timeId = setTimeout(() => {
    isScroll.value = true;
  }, 2000);
};

// 滚动监听器
const onScroll = ()=> {
  if(!isScroll.value) return
  // 获取所有锚点元素
  const navContents = document.querySelectorAll('.container .section')
  // 所有锚点元素的 offsetTop
  const offsetTopArr = []
  navContents.forEach(item => {
    offsetTopArr.push(item.offsetTop-30)
  })
  // 获取当前文档流的 scrollTop
  const scrollTop = document.getElementById('scrollBox').scrollTop
  // 定义当前点亮的导航下标
  let navIndex = 1
  for (let n = 1; n <= offsetTopArr.length; n++) {
    // 如果 scrollTop 大于等于第 n 个元素的 offsetTop 则说明 n-1 的内容已经完全不可见
    // 那么此时导航索引就应该是 n 了
    if (scrollTop >= offsetTopArr[n-1]) {
      navIndex = n
    }
  }
  // 把下标赋值给 vue 的 data
  activeIndex.value = navIndex
}

</script>
<style scoped lang="scss">
.box{
  // width: 98%;
  margin: auto;
  height: 100%;
  overflow: auto;
}
.fixed-box{
  width: calc(100% - 200px);
  background: white;
  position: fixed;
  top: 84px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 99;
  padding: 5px 30px;
  box-sizing: border-box;
  box-shadow: 1px 1px 1px #ccc;
  span {
    padding: 0 10px;
    list-style: none;
  }
}
.container {
  padding-top: 15px;
  position: relative;
}
.section {
  margin: 20px 0;
}
:deep(.el-tabs ){
  --el-tabs-header-height: 50px;
}
.active_anchor {
  color: #409eff;
}
</style>