1.
<script language="JavaScript">
//日期
var now = new Date(); //获取系统日期，即Sat Jul 29 08:24:48 UTC+0800 2006
var yy = now.getYear(); //截取年，即2006
var mm = now.getMonth(); //截取月，即07
var dd = now.getDay(); //截取日，即29
//取时间
var hh = now.getHours(); //截取小时，即8
var mm = now.getMinutes(); //截取分钟，即34
var ss = now.getTime() % 60000; //获取时间，因为系统中时间是以毫秒计算的，
所以秒要通过余60000得到。
ss = (ss - (ss % 1000)) / 1000; //然后，将得到的毫秒数再处理成秒
var clock = hh+':'; //将得到的各个部分连接成一个日期时间
if (mm < 10) clock += '0'; //字符串
clock += mm+':';
if (ss < 10) clock += '0';
clock += ss;
</script>
2.
</head>
<body>
<script language="javascript">
var week;
if(new Date().getDay()==0) week="周日"
if(new Date().getDay()==1) week="周一"
if(new Date().getDay()==2) week="周二"
if(new Date().getDay()==3) week="周三"
if(new Date().getDay()==4) week="周四"
if(new Date().getDay()==5) week="周五"
if(new Date().getDay()==6) week="周六"
document.write((new Date().getMonth()+1)+"月"+new Date().getDate()+"日 "+week);
</script>
</body>
</html>
3.
<!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" xml:lang="en" lang="en">
<head>
<title></title>
<script type="text/javascript">
function clock(){
var nowtime=new Date();
var flag="AM";
var hours=nowtime.getHours();
if(hours>12){
hours-=12;
flag="PM";
}
hours=hours>9?hours:"0"+hours;
var minutes=nowtime.getMinutes();
minutes=minutes>9?minutes:"0"+minutes;
var seconds=nowtime.getSeconds();
seconds=seconds>9?seconds:"0"+seconds;
var disptime=hours+":"+minutes+":"+seconds+" "+flag;
document.getElementById("clock").innerHTML=disptime;
setTimeout("clock()",1000);
}
</script>
</head>
<body>
<div id="clock"></div>
<script type="text/javascript">
clock();
</script>
</body>
</html>