<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
</style>
</head>
<body>
<div id="app">
<input type="text" v-model.trim='a' @input='add'>
<p>{{a}}</p>
</div>
<script src="js/vue.js"></script>
<script>
var vue = new Vue({
el:"#app",
data:{
a: 100
},
methods:{
add() {
console.log(this.a)
}
}
})
</script>
</body>
</html>