效果如下：
代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
#box {
width: 400px;
height: 502px;
border: 2px solid orange;
margin: 50px auto;
font-size: 48px;
text-align: center;
}
#ym {
height: 100px;
line-height: 100px;
}
#d {
height: 200px;
line-height: 200px;
background-color: orange;
font-size: 72px;
}
#w {
height: 100px;
line-height: 100px;
}
#hms {
height: 100px;
line-height: 100px;
}
</style>
</head>
<body>
<div id="box">
<div id="ym"></div>
<div id="d"></div>
<div id="w"></div>
<div id="hms"></div>
</div>
<script>
//调用 getDateAndTime方法
getDateAndTime();
//启动定时器，调用 getDateAndTime方法
window.setInterval(getDateAndTime, 1000);
function getDateAndTime() {
//获取系统当前的日期时间
var date = new Date();
//提取日期时间构成的元素
var year = date.getFullYear();
var month = date.getMonth() + 1;
var day = date.getDate();
var week = date.getDay();
var hour = date.getHours();
var minute = date.getMinutes();
var second = date.getSeconds();
//处理week的格式
switch (week) {
case 0:
week = '星期日';
break;
case 1:
week = '星期一';
break;
case 2:
week = '星期二';
break;
case 3:
week = '星期三';
break;
case 4:
week = '星期四';
break;
case 5:
week = '星期五';
break;
case 6:
week = '星期六';
break;
}
//定义函数处理时分秒的格式
function formatHMS(time) {
if (time < 10) {
return '0' + time;
} else {
return time;
}
}
//获取页面元素
var ym = document.getElementById('ym');
var d = document.getElementById('d');
var w = document.getElementById('w');
var hms = document.getElementById('hms');
//将日期时间写入到页面
ym.innerHTML = year + '年' + month + '月';
d.innerHTML = day;
w.innerHTML = week;
hms.innerHTML = hour + '时' + minute + '分' + second + '秒';
}
</script>
</body>
</html>
