js实现的时钟
<html>
<head>
<script type="text/javascript">
function startTime()
{
var today=new Date()
var h=today.getHours()
var m=today.getMinutes()
var s=today.getSeconds() // add a zero in front of numbers<10
m=checkTime(m)
s=checkTime(s)
document.getElementById('txt').innerHTML=h+":"+m+":"+s
t=setTimeout('startTime()',500) }
function checkTime(i)
{ if (i<10) {i="0" + i} return i }
</script>
</head>
<body onload="startTime()">
<div id="txt"></div>
</body>
</html>