## 生命周期函数(钩子)  ```javascript var vm = new Vue({ el:"#app", //template:"<div>{{abc}}</div>", data:{ abc:'abcdefg', }, beforeCreate:function(){ console.log('beforeCreate'); }, created:function(){ console.log('created'); }, beforeMount:function(){ console.log(this.$el); }, mounted:function(){ console.log(this.$el); }, beforeUpdate:function(){ console.log('beforeUpdate'); }, updated:function(){ console.log('updated'); }, }) ```