Javascript a odpočítávání startu

gistfile1.js

<script language="JavaScript">
var timerID = null; 
var timerRunning = false; 
function showtime() { 
today = new Date(); 
BigDay = new Date("october 6, 2011 10:00:00") 
msPerDay = 24 * 60 * 60 * 1000 ; 
timeLeft = (BigDay.getTime() - today.getTime()); 
e_daysLeft = timeLeft / msPerDay; 
daysLeft = Math.floor(e_daysLeft); 
e_daysLeft = timeLeft / msPerDay; 
daysLeft = Math.floor(e_daysLeft); 
e_hrsLeft = (e_daysLeft - daysLeft)*24; 
hrsLeft = Math.floor(e_hrsLeft); 
minsLeft = Math.floor((e_hrsLeft - hrsLeft)*60); 
hrsLeft = hrsLeft; 
e_minsLeft = (e_hrsLeft - hrsLeft)*60; 
secLeft = Math.floor(e_hrsLeft); 
secLeft = Math.floor((e_minsLeft - minsLeft)*60); 
secLeft = secLeft; 
Temp3='Do akce zbývá '+daysLeft+' dní, '+hrsLeft+' hodin, '+minsLeft+' minut, '+secLeft+' sekund.'
if(daysLeft < 0){Temp3='Odpočítávání skončilo!'};
document.getElementById('cas').innerHTML = Temp3;
timerID = setTimeout("showtime()",1000); 
timerRunning = true; 
}
var timerID = null;
var timerRunning = false;
function stopclock () {
if(timerRunning)
clearTimeout(timerID);
timerRunning = false;
}
function stopClock() {
stopclock();    
return;
}
function startclock () {
stopclock();
showtime()
}
document.write("<span id='cas'> </span>");
startclock ();
</script>