实现效果如下  不管是点击还是  滚动鼠标 顶部的样式也会跟随变化

点击会跳转到指定的位置 

通过IntersectionObserver 监听是否可见 

下面代码可以直接执行到vue的文件 

<template><div><ul class="nav"><li v-for="tab in tabs" :key="tab.name" :class="{ active: currentTab === tab.name }" @click="scrollToTab(tab)">{{ tab.label }}</li><div class="underline" :style="underlineStyle"></div></ul><div class="section" id="section1">Section 1</div><div class="section" id="section2">Section 2</div><div class="section" id="section3">Section 3</div><div class="section" id="section4">Section 4</div><div class="section" id="section5">Section 5</div></div>
</template><script>
export default {data () {return {currentTab: 'tab1',tabs: [{ name: 'tab1', label: '首页', id: 'section1' },{ name: 'tab2', label: '服务内容', id: 'section2' },{ name: 'tab3', label: '业务案例', id: 'section3' },{ name: 'tab4', label: '关于我们', id: 'section4' },{ name: 'tab5', label: '联系方式', id: 'section5' }],underlineStyle: {width: '0px',left: '0px'}}},methods: {scrollToTab (section) {this.currentTab = section.namethis.updateUnderline()const element = document.getElementById(section.id)document.getElementById(section.id).scrollIntoView({ behavior: 'smooth', block: 'center' })},updateUnderline () {this.$nextTick(() => {const activeTab = this.$el.querySelector('.nav .active')if (activeTab) {this.underlineStyle.width = `${activeTab.offsetWidth}px`this.underlineStyle.left = `${activeTab.offsetLeft}px`}})},handleIntersection (entries) {entries.forEach((entry) => {if (entry.isIntersecting) {const tab = this.tabs.find((tab) => tab.id === entry.target.id)if (tab) {this.currentTab = tab.namethis.updateUnderline()}}})}},mounted () {this.updateUnderline()const options = {root: null,rootMargin: `-${this.$el.querySelector('.nav').offsetHeight}px 0px 0px 0px`,threshold: 0.5}const observer = new IntersectionObserver(this.handleIntersection, options)this.tabs.forEach((tab) => {const section = document.getElementById(tab.id)if (section) {observer.observe(section)}})window.addEventListener('resize', this.updateUnderline)},beforeDestroy () {window.removeEventListener('resize', this.updateUnderline)}
}
</script><style scoped>
.nav {display: flex;position: fixed;top: 0;width: 1000px;background-color: white;z-index: 1000;border-bottom: 1px solid #ccc;
}
.nav li {flex: 1;text-align: center;padding: 10px;cursor: pointer;position: relative;
}
.nav li.active {color: blue;
}
.underline {position: absolute;bottom: 0;height: 2px;background-color: blue;transition: width 0.3s, left 0.3s;
}
.section {height: 300px;padding-top: 60px; /* 留出导航栏的高度 */border-bottom: 1px solid #ccc;
}
</style>