<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
#box{
width:150px;
height:150px;
background-color:red;
}
</style>
</head>
<body>
<div id="box"></div>
<script>
var box=document.getElementById("box");
var change=0;
var timer=null;
//监听盒子的鼠标移入事件
box.onmouseover=function(){
//清除定时器
clearInterval(timer);
//开启定时器
timer=setInterInterval(function(){
change+=1;
consoel.log(change);
},1000);
}
</script>
</body>
</html>
原文：https://www.cnblogs.com/zhang-jiao/p/9690387.html