var leave = new Date("December 01 2011 00:00:00")
function CalcRemaining(theForm)
{
var now = new Date();

var difference = parseInt(((leave.getTime() - now.getTime()) / 1000) + 0.999)
var secs = difference % 60

difference = parseInt(difference / 60)
var minutes  = difference % 60

difference = parseInt(difference / 60)
var hours  = difference % 24

difference = parseInt(difference / 24)
var days  = difference

theForm.txtDays.value = days;
theForm.txtHours.value = hours;
theForm.txtMins.value = minutes;
theForm.txtSecs.value = secs;

setTimeout("CalcRemaining(document.clock)", 250);
}