ElementUI之el-scrollbar + el-backtop + el-timeline实现时间轴触底刷新和一键返回页面顶部。
背景：ElementUI的版本（vue.global.js = 3.2.36， index.css = 2.4.4， index.full.js = 2.4.4）
废话不多说，先看动图效果↓↓↓
然后直接上代码。（注意代码中有注释的地方，是容易出错的关键地方。）
<html><head><meta charset="UTF-8" /><meta name="viewport" content="width=device-width,initial-scale=1.0" /><!-- viewport设置, 简单页面兼容手机端显示 --><script src="https://unpkg.com/vue@3.2.36/dist/vue.global.js"></script><link rel="stylesheet" href="https://unpkg.com/element-plus@2.4.4/dist/index.css"><script src="https://unpkg.com/element-plus@2.4.4/dist/index.full.js"></script><title>Test Web Page</title><style>.el-timeline {padding-left: 0;}</style></head><body><div id="app" class="allpack" style="height:100%;overflow: hidden;"><!-- 最外层overflow要设置为hidden, 否则会和el-scrollbar冲突, 显示2个滚动条且滚动不舒服--><el-scrollbar class="scrollbar" ref="scrollbar" style="height:100%;"><el-backtop target=".scrollbar .el-scrollbar__wrap" :bottom="100"><!-- 这里设置target除了添加el-scrollbar本体,还要添加.el-scrollbar__wrap, 否则无效 --><divstyle="height: 100%;width: 100%;background-color: var(--el-bg-color-overlay);box-shadow: var(--el-box-shadow-lighter);text-align: center;line-height: 40px;color: #1989fa;">UP</div></el-backtop><h1 align="center">Test Message</h1><el-row><!-- 只是为了给布局添加自适应的边距, 不重要, 读者可不使用 --><el-col :span="1"><div class="grid-content ep-bg-purple"></div></el-col><el-col :span="22"><div class="grid-content ep-bg-purple-light"><el-timeline><el-timeline-itemv-for="(activity, index) in activities"placement="top":key="index":timestamp="activity.timestamp"><el-card><h4>{{ activity.content }}</h4><p>{{ activity.timestamp }}</p></el-card></el-timeline-item></el-timeline></div></el-col><el-col :span="1"><div class="grid-content ep-bg-purple"></div></el-col></el-row></el-scrollbar></div><script>const App = {data() {return {message: "Hello Element Plus",activities: [{content: 'Custom icon',timestamp: '2018-04-12 20:46',},{content: 'Custom color',timestamp: '2018-04-03 20:46',},{content: 'Custom size',timestamp: '2018-04-03 20:46',},{content: 'Custom hollow',timestamp: '2018-04-03 20:46',},{content: 'Default node',timestamp: '2018-04-03 20:46',},{content: 'Custom hollow',timestamp: '2018-04-03 20:46',},{content: 'Default node',timestamp: '2018-04-03 20:46',},{content: 'Custom hollow',timestamp: '2018-04-03 20:46',},{content: 'Default node',timestamp: '2018-04-03 20:46',},]};},methods: {updateData() {var obj = {content: 'aaaaaaaa',timestamp: '2023-04-03 20:46',};this.activities.push(obj);this.activities.push(obj);this.activities.push(obj);this.activities.push(obj);this.activities.push(obj);this.activities.push(obj);},scrollerFunc() {//这里要注意用document.getElementById去获取scrollbar组件读取滚动距离值是错误的,要用this.$refs.scrollbar.$ellet let1 = this.$refs.scrollbar.$el.firstChild.scrollTop; //滚动条滚动距离let let2 = this.$refs.scrollbar.$el.firstChild.scrollHeight; //浏览器总高度let let3 = this.$refs.scrollbar.$el.scrollHeight; //浏览器可见高度console.log(let1, let2, let3);if(let1 + let3 == let2){console.log("页面触底啦")let loadingInstance = this.$loading({target: "#load",text: "加载中"});setTimeout(() => {//你用的时候这里就可以访问后端数据进行更新，我这里直接本地更新数据了this.updateData();loadingInstance.close();}, 1000);}}},mounted() {this.$refs.scrollbar.$el.addEventListener("scroll", this.scrollerFunc, true); //这里要注意用document.getElementById去获取scrollbar组件绑定滚动事件无效，要使用this.$refs.scrollbar.$el}};const app = Vue.createApp(App);app.use(ElementPlus);app.mount("#app");</script></body>
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为避免篇幅过长，更多细节的处理、集成分页功能等就不在此展示了，完全可自行实现。
