Lo scopo?

Minimalista:
codice:
<script>
var ss=-1;
function rovescio() {
	document.getElementById('pippo').innerHTML = (new Date(0,0,0,0,0,ss--)).toString().split(" ")[3]
}
</script>
<body onload="setInterval('rovescio()',1000)">
<div id="pippo">24:00:00</div>
ciao