Vue表單demo v-model雙向綁定問題

<div id="app">
 <textarea v-model = "message" placeholer = '請在此輸入文字'></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="閱讀" v-model="data.interest"/>
 <lable for="item1">閱讀</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="體操" v-model="data.interest"/>
 <lable for="checkbox">體操</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>