我这样写怎么样？有什么不好的地方吗

源自：8-17 编程练习

<!DOCTYPE html>

<html>

<head>

<title>浏览器对象</title>

</head>

<body>

<p>

<strong id="times">5</strong>秒后返回到主页<a href="https://www.imooc.com">&nbsp返回</a>

</p>

var num=5,cancel;

function back1(){

var time=document.getElementById("times");

time.firstChild.nodeValue=num;

num=num-1;

cancel=setTimeout("back1()",1000);

if(num==0){

clearTimeout(cancel);

window.open("https://www.imooc.com","_self");

}

setTimeout("back1()",300);

</script>

</body>

</html>

提问者：轻新无限sou 2018-09-23 17:04