1.代碼
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Vue-監聽屬性/雙向數據綁定</title>
<script src="https://cdn.staticfile.org/vue/2.4.2/vue.min.js"></script>
</head>
<body>
<div id = "app">
<p style = "font-size:25px;">計數器: {{ counter }}</p>
<input v-model="counter">
<button @click = "counter++" style = "font-size:25px;">點我</button>
</div>
<script type = "text/javascript">
var vm = new Vue({
el: '#app',
data: {
counter: 1
}
});
vm.$watch('counter', function(nval, oval) {
alert('計數器值的變化 :' + oval + ' 變爲 ' + nval + '!');
});
</script>
</body>
</html>
2.效果
3.代碼分析
