DOME_HTML/watch.html

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>wacth 的使用</title>
<meta name="description" content="">
<meta name="keywords" content="">
<link href="" rel="stylesheet">
</head>
<body>
    <div id='app'>
    	<input type="text" v-model='searchQuery'>
    	<p v-if='isSearch' >search...</p>
    	<div v-else >
    		<ul>
						<li v-for='(item,index) in items' v-cloak>{{ item }}</li>
    		</ul>
    	</div>
    </div>
    <script type="text/javascript" src='js/vue.min.js'></script>
    <script>
    	let vm=new Vue({
    		el:"#app",
    		data:{
    			searchQuery:'search',
    			isSearch:true,
    			items:[]
    		},
    		watch:{
    			searchQuery:function(query){
    				this.isSearch=false;
    				this.items.push(query);
    			}

    		}
    	});
    	//$watch
    	vm.$watch('searchQuery',function(){
    		alert(1);
    	})
    </script>
</body>
</html>