Vue表单demo v-model双向绑定问题

<div id="app"> <textarea v-model = "message" placeholer = '请在此输入文字'></textarea> <span>{{message}}</span>  </br> <input type="text" v-model="data.name"/> <span>姓名：{{data.name}}</span> </br> <input type="radio" id="boy" value="男" v-model="data.gender"/> <label for="boy">男</label> <input type="radio" id="girl" value="女" v-model="data.gender"/> <lable for="girl">女</lable> <span>{{data.gender}}</span> <br/> <input type="checkbox" id="item1" value="阅读" v-model="data.interest"/> <lable for="item1">阅读</lable> <input type="checkbox" id="item2" value="打球" v-model="data.interest"/> <lable for="item2">打球</lable> <input type="checkbox" id="item3" value="体操" v-model="data.interest"/> <lable for="checkbox">体操</lable> <br/> <span>{{data.interest}}</span> <select v-model="data.identity">  <option value="java" selected>java</option>  <option value="web">web</option>  <option value="hr">hr</option> </select> <span>身份：{{data.identity}}</span></div><script src="js/vue.js"></script><script> new Vue({  el: '#app',  data: {   message: '6',   data: {    name: '',    gender: '',    interest: [],    identity: ''   },  } })</script>