JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//unpkg.com/vue/dist/vue.js"></script>
<script src="//unpkg.com/[email protected]/lib/index.js"></script>
<div id="app">
  <el-button @click="activeIndex = activeIndex === '1' ? '4' : '1'">Change Active Index</el-button>
  <el-menu :default-active="activeIndex" mode="horizontal" @select="handleSelect">
    <el-menu-item index="1">处理中心</el-menu-item>
    <el-submenu index="2">
      <template slot="title">我的工作台</template>
      <el-menu-item index="2-1">选项1</el-menu-item>
      <el-menu-item index="2-2">选项2</el-menu-item>
      <el-menu-item index="2-3">选项3</el-menu-item>
      <el-submenu index="2-4">
        <template slot="title">选项4</template>
        <el-menu-item index="2-4-1">选项1</el-menu-item>
        <el-menu-item index="2-4-2">选项2</el-menu-item>
        <el-menu-item index="2-4-3">选项3</el-menu-item>
      </el-submenu>
    </el-submenu>
    <el-menu-item index="3" disabled>消息中心</el-menu-item>
    <el-menu-item index="4"><a href="https://www.ele.me" target="_blank">订单管理</a></el-menu-item>
  </el-menu>
</div>

SCSS

@import url("//unpkg.com/[email protected]/lib/theme-chalk/index.css");

Babel + JSX

var Main = {
    data() {
      return {
        activeIndex: '1'
      };
    },
    methods: {
      handleSelect(key, keyPath) {
        console.log(key, keyPath);
      }
    }
  }
var Ctor = Vue.extend(Main)
new Ctor().$mount('#app')