text: <!DOCTYPE html>
  <html lang="en">
  <head>
      <meta charset="UTF-8">
      <title>Title</title>
      <script src="vue.js"></script>
  </head>
  <body>
  <div id="components-demo">
      <button-counter id="123"></button-counter>
  </div>
  <div id="app">
      {{ message }}
  </div>
  
  <script>
      //   function  person (){
      //     this.options='aaa'
      //   }
      //
      //   person.constructor={aa:'c'}
      //   person.prototype.options='span'
      //
      //   console.log(person.constructor.options)
      //  console.log(Object.create(person.constructor.options));
      //    new Vue({})
      var obj = {
          name: 'name',
          age: 29
      }
      var arr = []
      var res = new Array(obj.length);
  
      console.log(obj.length)
      console.log(res)
      console.log(arr.length)
  
  
      Vue.component('button-counter', {
          props:['id'],
          functional:true,
          inject: ['foo'],
          data: function () {
              return {
                  count: 0
              }
          },
          mounted: ()=> { //挂载元素，获取到DOM节点
              console.log('==this.foo==')
              console.log(this.foo)
  
          },
          template: '<button v-on:click="count++">You clicked me {{ count }} times.</button>'
      })
  
      new Vue({el: '#components-demo'})
  
      var app = new Vue({
          el: '#app',
          provide: {
              foo: 'bar'
          },
          beforeCreate(){
  
          },
          created(){
  
          },
          beforeMount(){
  
          },
          mounted: ()=> { //挂载元素，获取到DOM节点
  
             setTimeout(()=>{
                  this.count=11;
                  console.log('this.count='+this.count)
             },5000)
          },
          beforeUpdate(){
  
          },
          updated(){ //挂载元素，获取到DOM节点
          },
          beforeDestroy(){
  
          },
          destroyed(){
  
         },
          data: {
              count:0,
              message: 'Hello Vue!'
          }
      })
  </script>
  
  </body>
  </html>