js 动态时钟

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<script type="text/javascript">
//实例:动态时钟
/*
(1)时间日期信息,应该在一个<div>中来显示
(2)定时器:每隔一秒再次访问系统时间,window对象的setTimeout()
(3)时钟显示的时机(事件):当网页加载完成后才显示,事件onload
(4)如何将 时间日期信息 写入到指定的<div>中,DOM对象中的innerHTML属性
*/ //定义函数:构建要显示的时间日期字符串
function showTime()
{
//创建Date对象
var today = new Date();
//分别取出年、月、日、时、分、秒
var year = today.getFullYear();
var month = today.getMonth()+1;
var day = today.getDate();
var hours = today.getHours();
var minutes = today.getMinutes();
var seconds = today.getSeconds();
//如果是单个数,则前面补0
month = month<10 ? "0"+month : month;
day = day <10 ? "0"+day : day;
hours = hours<10 ? "0"+hours : hours;
minutes = minutes<10 ? "0"+minutes : minutes;
seconds = seconds<10 ? "0"+seconds : seconds; //构建要输出的字符串
var str = year+"年"+month+"月"+day+"日 "+hours+":"+minutes+":"+seconds; //获取id=result的对象
var obj = document.getElementById("result");
//将str的内容写入到id=result的<div>中去
obj.innerHTML = str;
//延时器
window.setTimeout("showTime()",1000);
}
</script>
<style type="text/css">
#result{
width:500px;
border:1px solid #CCCCCC;
background:#FFFFCC;
margin:50px auto;
font-size:24px;
color:#FF0000;
padding:20px;
}
</style>
</head> <body onload="showTime()">
<div id="result"></div>
</body>
</html>
04-27 17:27