<div id="example">
 <parent-component></parent-component>
</div>
<template id="parent-component">
 <div class="parent">
 <h3>我是父组件</h3>
 <input v-model="parentMsg">
 <p>{{parentMsg}}</p>
 <child-component></child-component> 
 </div>
</template>
<template id="child-component">
 <div class="child">
 <h3>我是子组件</h3>
 <p>{{msg}}</p>
 <button v-on:click="showData">显示父组件数据</button> 
 </div>
</template>

<script>
// 注册
Vue.component('parent-component', {
 template: '#parent-component',
 data(){
 return{
  parentMsg:'我是父组件的数据'
 }
 },
 components:{
 'child-component':{
  template:'#child-component',
  data(){
  return{
   msg:''
  }
  },
  methods:{
  showData(){
   this.msg = this.$parent.parentMsg;
  }
  }
 }
 }
})
// 创建根实例
new Vue({
 el: '#example'
})
</script>

<div id="example">
 <h3>我是根组件</h3>
 <input v-model="rootMsg">
 <p>{{rootMsg}}</p> 
 <parent-component></parent-component>
</div>
<template id="parent-component">
 <div class="parent">
 <h3>我是父组件</h3>
 <input v-model="parentMsg">
 <p>{{parentMsg}}</p>
 <child-component></child-component> 
 </div>
</template>
<template id="child-component">
 <div class="child">
 <h3>我是子组件</h3>
 <p>
  <button v-on:click="showRootData">显示根组件数据</button><span>{{rootMsg}}</span>
 </p>  
 <p>
  <button v-on:click="showParentData">显示父组件数据</button><span>{{parentMsg}}</span>
 </p>
 </div>
</template>

<script>
// 注册
Vue.component('parent-component', {
 template: '#parent-component',
 data(){
 return{
  parentMsg:'我是父组件的数据'
 }
 },
 components:{
 'child-component':{
  template:'#child-component',
  data(){
  return{
   parentMsg:'',
   rootMsg:''
  }
  },
  methods:{
  showParentData(){
   this.parentMsg = this.$parent.parentMsg;
  },
  showRootData(){
   this.rootMsg = this.$root.rootMsg;
  },  
  }
 }
 }
})
// 创建根实例
new Vue({
 el: '#example',
 data:{
 rootMsg:'我是根组件数据'
 }
})
</script>

<div id="example">
 <parent-component></parent-component>
</div>
<template id="parent-component">
 <div class="parent">
 <h3>我是父组件</h3>
 <button @click="getData">获取子组件数据</button>
 <br>
 <div v-html="msg"></div>
 <child-component1></child-component1> 
 <child-component2></child-component2> 
 </div>
</template>
<template id="child-component1">
 <div class="child">
 <h3>我是子组件1</h3>
 <input v-model="msg">
 <p>{{msg}}</p>
 </div>
</template>
<template id="child-component2">
 <div class="child">
 <h3>我是子组件2</h3>
 <input v-model="msg">
 <p>{{msg}}</p>
 </div>
</template>

<script>
// 注册
Vue.component('parent-component', {
 template: '#parent-component',
 data(){
 return{
  msg:'',
 }
 },
 methods:{
 getData(){
  let html = '';
  let children = this.$children;
  for(var i = 0; i < children.length;i++){
  html+= '<div>' + children[i].msg + '</div>';
  }
  this.msg = html;
 }
 },
 components:{
 'child-component1':{
  template:'#child-component1',
  data(){
  return{
   msg:'',
  }
  },
 },
 'child-component2':{
  template:'#child-component2',
  data(){
  return{
   msg:'',
  }
  },
 }, 
 } 
})
// 创建根实例
new Vue({
 el: '#example',
})
</script>

<child-component1 ref="c1"></child-component1>
<child-component2 ref="c2"></child-component2>

<div id="example">
 <parent-component></parent-component>
</div>
<template id="parent-component">
 <div class="parent">
 <h3>我是父组件</h3>
 <div>
  <button @click="getData1">获取子组件c1的数据</button>
  <p>{{msg1}}</p>
 </div>
 <div>
  <button @click="getData2">获取子组件c2的数据</button>
  <p>{{msg2}}</p>
 </div>
 <child-component1 ref="c1"></child-component1> 
 <child-component2 ref="c2"></child-component2> 
 </div>
</template>
<template id="child-component1">
 <div class="child">
 <h3>我是子组件1</h3>
 <input v-model="msg">
 <p>{{msg}}</p>
 </div>
</template>
<template id="child-component2">
 <div class="child">
 <h3>我是子组件2</h3>
 <input v-model="msg">
 <p>{{msg}}</p>
 </div>
</template>

<script>
// 注册
Vue.component('parent-component', {
 template: '#parent-component',
 data(){
 return{
  msg1:'',
  msg2:'',
 }
 },
 methods:{
 getData1(){
  this.msg1 = this.$refs.c1.msg;
 },
 getData2(){
  this.msg2 = this.$refs.c2.msg;
 }, 
 },
 components:{
 'child-component1':{
  template:'#child-component1',
  data(){
  return{
   msg:'',
  }
  },
 },
 'child-component2':{
  template:'#child-component2',
  data(){
  return{
   msg:'',
  }
  },
 }, 
 } 
})
// 创建根实例
new Vue({
 el: '#example',
})
</script>