today = new Date(); 

BigDay = new Date("September 15, 2010") 

msPerDay = 24 * 60 * 60 * 1000 ; 

timeLeft = (BigDay.getTime() - today.getTime()); 

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); 

document.write(""+daysLeft+" days, "+hrsLeft+" hours, "+minsLeft+" minutes");