<html>
<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>Document</title>
</head>
<body>
<div id="app">
<p v-once>原始值：{{msg}}</p>
<p>后面的：{{msg}}</p>
<input type="text" v-model="msg">
</div>
<script type="text/javascript" src="../assets/js/vue.js"></script>
<script>
new Vue({
el:'#app',
data () {
return {
msg:'今天天气很好'
}
}
})
</script>
</body>
</html>原始值不加v-once效果
原始值加上v-once的效果图
加上v-once的标签内容不受v-model影响