先上效果图，解释都在代码注释里边
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document
</title>
</head>
<body>
<div id="app">
<input type="button" value="帅起来" @click='shuai'>
<input type="button" value="歇会儿" @click='stop'>
<div>{{ msg }}</div>
</div>
<script src="https://unpkg.com/vue@2.6.10/dist/vue.js"></script>
<script>
var vm = new Vue({
el: '#app',
data: {
msg: '屏幕前的你，很帅~~~',
intervalId: null //在data上定义 定时器ID
},
methods: {
shuai() { // 开启跑动
if (this.intervalId != null) return//设置一个锁，防止开启多个定时器
this.intervalId = setInterval(() => {
let start = this.msg.substring(0, 1)//获取到头的第一个字符
let end = this.msg.substring(1)//获取到 后面的所有字符
this.msg = end + start //重新拼接得到新的字符串并赋值给this.msg
}, 400)
},
stop() { //停止定时器
clearInterval(this.intervalId)//清理定时期
this.intervalId = null//再把this.intervalId设置为null(暂停后可以再次开启跑动)
}
}
})
</script>
</body>
</html>