<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>vue 入门</title>
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="app">
姓 <input type="text" v-model='firstname'>
名 <input type="text" v-model="lastname">
<span>{{ fullName }}</span>
<span>{{ count }} </span>
</div>
<script>
new Vue({
el:"#app",
data:{
firstname:'',
lastname:'',
count:0
},
computed:{
fullName (){
return this.firstname + this.lastname
}
},
watch:{
fullName:function(){
this.count++
}
}
})
</script>
</body>
</html>