拷贝下面的代码到你的html文件的<body>和</body>之间；
<table border="0" width="100%" cellspacing="0" cellpadding="0">
<tr>
<td width="100%"><script language="JavaScript"><!--
var enabled = 0; today = new Date();
var day; var date;
if(today.getDay()==0) day = "星期日"
if(today.getDay()==1) day = "星期一"
if(today.getDay()==2) day = "星期二"
if(today.getDay()==3) day = "星期三"
if(today.getDay()==4) day = "星期四"
if(today.getDay()==5) day = "星期五"
if(today.getDay()==6) day = "星期六"
document.fgColor = "000000";
date = " 今天是 " + (today.getYear()) + " 年" + (today.getMonth() + 1 ) + " 月 " + today.getDate() + " 日 " + day +"";
document.write("<CENTER><TABLE BORDER=2 BGCOLOR=000000><TH><FONT COLOR=ffffff>")
document.write("<CENTER>" + date.fontsize(3) + "</CENTER>");
document.write("</FONT></TH></TABLE></center><P>")// -->
</script></td>
</tr>
</table>
