<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
</head>
<body>
<div id="app">
<p>{{ message }}</p>
<!-- 只能輸入數字 -->
<input type="number" name="" id="" value="" v-model.number="message" />
</div>
<script>
const app = new Vue({
el: '#app',
data: {
message: 'Hello Vue.js!',
},
})
</script>
</body>
</html>
