<!DOCTYPE?html>
<html?lang="en">
<head>
????<meta?charset="UTF-8">
????<title></title>
????<script?src="./vue.js"></script>
</head>
<body>
????<div?id="root">
????????姓：<input?v-model:value="firstName">
????????名：<input?v-model:value="lastName">
????????<div>{{fullName}}</div>
????????<div>{{count}}</div>
????</div>
????<script>
????????new?Vue({
????????????el:"#root",
????????????data:{
????????????????firstName:"",
????????????????lastName:"",
????????????????count:?0
?},
????????????computed:{
????????????????fullName:?function?()?{
????????????????????return?this.firstName+"?"+this.lastName
?}
????????????},
????????????watch:{
????????????????firstName:?function?()?{
????????????????????this,count++
????????????????}
????????????}
????????})
????</script>
</body>
</html>
2018-09-02
①你的點寫成了逗號?
?②firstName 改成 fullName即可