codice:
<!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>Documento senza titolo</title>
<script type="text/javascript"> 
function OrologioScorrevole() {     
	  var data = new Date();     
	  var hh = data.getHours();     
	  var mm = data.getMinutes();     
	  var ss = data.getSeconds();     
	  var ora = hh + ":" + mm + ":" + ss;     
	  document.getElementById("orologio").innerHTML = ora;     
	  window.setTimeout("OrologioScorrevole()", 1000);  
}
</script>
</head>
<body onload="OrologioScorrevole()">
<span id="orologio"></span>
</body>
</html>