Пойдет?
<div>Осталось <span id="my_timer"></span></div>
<script>
var date = new Date(2013, 0) ;
var now = new Date ;
var ms = date - now ;
var hour = ms/1000/60/60^0 ;
var min = (ms-hour*1000*60*60)/1000/60^0 ;
var sec = (ms-hour*1000*60*60-min*1000*60)/1000^0 ;
var span = document.getElementById("my_timer") ;
var hours = (hour<10) ? "0"+hour : hour ;
var mins = (min<10) ? "0"+min : min ;
var secs = (sec<10) ? "0"+sec : sec ;
span.innerHTML = hours+":"+mins+":"+secs ;
function time() {
sec-- ;
if(sec<0) {
sec = 59 ;
min-- ;
} ;
if(min<0) {
min = 59 ;
hour-- ;
} ;
var hours = (hour<10) ? "0"+hour : hour ;
var mins = (min<10) ? "0"+min : min ;
var secs = (sec<10) ? "0"+sec : sec ;
span.innerHTML = hours+":"+mins+":"+secs ;
setTimeout(time, 1000) ;
} ;
setTimeout(time, 1000) ;
</script>