<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>