function calcage(secs, num1, num2, LeadingZero) {
  s = ((Math.floor(secs/num1))%num2).toString();
  if (LeadingZero && s.length < 2)
    s = "0" + s;
  return s;
}

function CountBack(secs, DisplayFormat, FinishMessage, CountStepper, LeadingZero, SetTimeOutPeriod) {
  if (secs < 0) {
    document.getElementById("cntdwn").innerHTML = FinishMessage;
    return;
  }
  DisplayStr = DisplayFormat.replace(/%%D%%/g, calcage(secs,86400,100000, LeadingZero));
  DisplayStr = DisplayStr.replace(/%%H%%/g, calcage(secs,3600,24, LeadingZero));
  DisplayStr = DisplayStr.replace(/%%M%%/g, calcage(secs,60,60, LeadingZero));
  DisplayStr = DisplayStr.replace(/%%S%%/g, calcage(secs,1,60, LeadingZero));

  document.getElementById("cntdwn").innerHTML = DisplayStr;

  setTimeout("CountBack(" + (secs+CountStepper) + ",'" + DisplayFormat + "','" +  FinishMessage + "'," +  CountStepper + "," +  LeadingZero + "," +  SetTimeOutPeriod  + ")", SetTimeOutPeriod);
}

function drawTimer(TargetDate, DisplayFormat, FinishMessage, CountStepper, LeadingZero)
{
	CountStepper = Math.ceil(CountStepper);
	var SetTimeOutPeriod = (Math.abs(CountStepper)-1)*1000 + 990;
	
	document.write('<span id="cntdwn"></span>');
	
	var dthen = new Date(TargetDate);
	var dnow = new Date();
	if(CountStepper>0) {
	  ddiff = new Date(dnow-dthen);
	}
	else {
		ddiff = new Date(dthen-dnow);
	}
	
	gsecs = Math.floor(ddiff.valueOf()/1000);
	
	
	CountBack(gsecs, DisplayFormat, FinishMessage, CountStepper, LeadingZero, SetTimeOutPeriod);
}