<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
</body>
<script type="text/javascript">
setInterval(function(){
var date = new Date();
var y = date.getFullYear();
var m = date.getMonth();
var d = date.getDate();
var h = date.getHours();
var min = date.getMinutes();
var s = date.getSeconds();
//今天是2018年2月23日 8:23:09
document.body.innerHTML = "今天是"+y+‘年‘ + num(m+1)+"月"+ num(d) + "日" + num(h)+":"+num(min)+":"+num(s)
},1000)
function num(n){
if (n<10) {
return "0"+ n;
}
return n
}
//
</script>
</html>
原文：https://www.cnblogs.com/beallaliu/p/9348048.html