<template>
 <div class="wrapper">
  <ul class="content"></ul>
  <button class="add" id="add" @click="add">添加子元素</button>
 </div>
</template>

<script>
export default {
 data() {
  return {};
 },
 methods: {
  add() {
   let ul = document.getElementsByClassName("content")[0]; 
   let li = document.createElement("li");
   li.innerHTML = "我是添加的元素";
   ul.appendChild(li);   
  }
 }
};
</script>
<style >
</style>

<template>
 <div id="app">
  <keep-alive>
   <router-view />
  </keep-alive>
</template>

//index.js
{
   path: '/1',
   name: 'components1',
   component: Components1,
   meta: {
    keepAlive: true  //判断是否缓存
   }
  },
  {
   path: '/2',
   name: 'components2',
   component: Components2,
   meta: {
     keepAlive: false
   }
  },

 <div id="app">
  <keep-alive>
   <router-view v-if="$route.meta.keepAlive" />
  </keep-alive>
  <router-view v-if="!$route.meta.keepAlive" />
</template>

//components1中
 created() {
  console.log("1激活created钩子函数");
 },
 activated() {
  console.log("1激活activated钩子函数");
 },
 mounted() {
  console.log("1激活mounted钩子函数");
 }

//components2中
 created() {
  console.log("2激活created钩子函数");
 },
 activated() {
  console.log("2激活activated钩子函数");
 },
 mounted() {
  console.log("2激活mounted钩子函数");
 }