window.addEventListener('scroll', this.handleScroll)  methods:{handleScroll () { var scrollTop = window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop var offsetTop = document.querySelector('#searchBar').offsetTop if (scrollTop > offsetTop) {  //判斷是否到達了頂部  this.searchBarFixed = true } else {  this.searchBarFixed = false }} }

<template><div> <div class="nav"></div><div class="searchBar" id="searchBar"> <ul :class="searchBarFixed == true ? 'isFixed' :''"> //用v-bind綁定樣式  <li>區域<i class="iconfont icon-jiantouxia"></i></li>  <li>價格<i class="iconfont icon-jiantouxia"></i></li>  <li>房型<i class="iconfont icon-jiantouxia"></i></li>  <li>更多<i class="iconfont icon-jiantouxia"></i></li> </ul></div><div class="content"></div></div></template><script> export default {  components:{  },mounted () { window.addEventListener('scroll', this.handleScroll)},    data(){     return {      searchBarFixed:false    }  },  methods:{handleScroll () { var scrollTop = window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop var offsetTop = document.querySelector('#searchBar').offsetTop if (scrollTop > offsetTop) {  this.searchBarFixed = true } else {  this.searchBarFixed = false }}, } }</script><style lang="less" scope>.nav{ height: 250px;}.content{ height: 1900px;}.searchBar{ .isFixed{  position:fixed;  background-color:#Fff;  top:0;  z-index:999; } ul {  width:100%;  height: 40px;  line-height: 40px;  display: flex;  li {   list-style: none;   font-size: 0.8rem;   text-align: center;   flex: 1;   i {    font-size: 0.9rem;    padding-left: 5px;    color: #ccc;   }  }  border-bottom: 1px solid #ddd; }}</style>