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

function UpdateTimer() {
	var dnow = new Date();
	//ddiff = new Date(dthen-dnow);
	gsecs = Math.floor((dthen.valueOf()-dnow.valueOf())/1000);
	
	
	DisplayStr = DisplayFormat.replace(/%%H%%/g, calcage(gsecs,3600,1000000));
	DisplayStr = DisplayStr.replace(/%%M%%/g, calcage(gsecs,60,60));
	DisplayStr = DisplayStr.replace(/%%S%%/g, calcage(gsecs,1,60));
	
	document.getElementById("turntimer").innerHTML = DisplayStr;

	setTimeout("UpdateTimer()", SetTimeOutPeriod);
}

var dthen;
var SetTimeOutPeriod;

function StartTimer(time) {
	DisplayFormat = "%%H%%:%%M%%:%%S%%";
	
	SetTimeOutPeriod = 990;
	var temptime = new Date()
	dthen = new Date(temptime.valueOf()+(time*1000));
	UpdateTimer();
}