today = new Date();
 BigDay = new Date("Feb,23,2012,19:30:00")
 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( "Осталось <b>"+daysLeft+"</b> дн. <b>"+hrsLeft+"</b> ч. и <b>"+minsLeft+"</b> мин.");