mounted 实例化之后
<div id="test"> {{a}} </div> var myVue = new Vue({ el: "#test", data: { a: "HelloWord" }, beforeCreate: function() { console.log("创建前") console.log(this.a) console.log(this.$el) }, created: function() { console.log("创建之后"); console.log(this.a) console.log(this.$el) }, beforeMount: function() { console.log("mount之前") console.log(this.a) console.log(this.$el) }, mounted: function() { console.log("mount之后") console.log(this.a) console.log(this.$el) }, beforeUpdate: function() { console.log("更新前"); console.log(this.a) }, updated: function() { console.log("更新完成"); console.log(this.a) }, beforeDestroy: function() { console.log("销毁前"); console.log(this.a) console.log(this.$el) }, destroyed: function() { console.log("已销毁"); console.log(this.a) console.log(this.$el) } });测试中，发现
beforeCreate创建之前 data是undefined、el也是undefined
created创建之后 data是a的值：HelloWord、el是undefined
beforeMount实例化之前 data是a的值：HelloWord、el是虚拟的（即<div id="test">{{a}}</div> ）
mounted实例化之后 data是a的值：HelloWord、el是真实的（即 <div id="test">HelloWord</div>）
