侦听器-immeaiate选项 

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<div id="app">
			<input type="text" v-model="username" />
		</div>
		<script src="vue-2.6.12.js"></script>
		<script src="jquery-v3.6.0.js"></script>
		<script>
			const vm = new Vue({
				el: '#app',
				data: {
					username: 'admin'
				},
				// 所有的侦听器，都应该被定义到watch节点下
				watch: {
					// 定义对象格式的侦听器
					username: {
						//侦听器的处理函数
						handler(newVal, oldVal) {
							console.log(newVal, oldVal)
						},
						//immediate选项的默认值是false
						immediate: true
					}
				}
			})
		</script>
	</body>
</html>
posted @ 2023-06-11 00:33  Young_Yang_Yang  阅读(17)  评论(0)  编辑  收藏  举报