<div id="app19">
   <my-component19 :count="1"></my-component19>
  </div>
Vue.component('my-component19',{
 name: 'my-component19', //其实当你利用 Vue.component 全局注册了一个组件，全局的ID会被自动设置为组件的name。
 props: {
  count: {
   type: Number,
   default: 1
  }
 },
 template: '<div><my-component19 :count="count+1" v-if="count<3"></my-component19></div>'
});
var app19 = new Vue({
 el: '#app19'
});

 <div id="app19">
  <div>
   <div>
    <div><!----></div>
   </div>
  </div>
 </div>

<div id="app20">
   <my-component20 inline-template>
    <div>
     <h3>在父组件中定义子组件的模板</h3>
     <p>{{msg}}</p>
    </div>
   </my-component20>
  </div>
Vue.component('my-component20',{
 data: function(){
  return {
   msg: '在子组件声明的数据'
  }
 }
});
var app20 = new Vue({
 el: '#app20'
});

<div id="app21">
   <component :is="currentView"></component>
   <button @click="changeView('A')">切换到A</button>
   <button @click="changeView('B')">切换到B</button>
   <button @click="changeView('C')">切换到C</button>
  </div>
var app21 = new Vue({
 el: '#app21',
 data: {
  currentView: 'comA'
 },
 methods: {
  changeView: function(data){
   this.currentView = 'com'+ data　　//动态地改变currentView的值就可以动态挂载组件了。
  }
 },
 components: {
  comA: {
   template: '<div>组件A</div>'
  },
  comB: {
   template: '<div>组件B</div>'
  },
  comC: {
   template: '<div>组件C</div>'
  }
 }
});

 <div id="app22">
      <my-component22></my-component22>
    </div>
Vue.component('my-component22',function(resolve, reject){
  window.setTimeout(function(){
    resolve({
      template: '<div>我是异步渲染的</div>'
    })
  },2000)
});

var app22 = new Vue({
  el: '#app22'
});