<!doctype html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<meta name="viewport"
content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css" rel="stylesheet">
<title>Document</title>
</head>
<body>
<div id="app">
<button class="btn btn-primary" @click="running">running</button>
<button class="btn btn-primary" @click="stop">stop</button>
<h3>{{message}}</h3>
</div>
<script src="vue.js"></script>
<script>
const app = new Vue({
el:"#app",
data:{
message:'但屈指西風幾時來，又不道流年暗中偷換.',
interval:null
},
methods:{
running(){
if(this.interval == null) {
this.interval = setInterval(function(){
let start = this.message.substring(0,1);
let end = this.message.substring(1);
this.message = end + start;
},500)
}
},
stop(){
clearInterval(this.interval)
this.interval = null
}
}
})
</script>
</body>
</html>
