var _countDowncontainer=0;
var _currentSeconds=0;

function ActivateCountDown(strContainerID, initialValue) {
	_countDowncontainer = document.getElementById(strContainerID);
	
	if (!_countDowncontainer) {
		alert("count down error: container does not exist: "+strContainerID+
			"\nmake sure html element with this ID exists");
		return;
	}
	
	SetCountdownText(initialValue);
	window.setTimeout("CountDownTick()", 1000);
}

function CountDownTick() {
	if (_currentSeconds <= 0) {
		alert("your time has expired!");
		return;
	}
	
	SetCountdownText(_currentSeconds-1);
	window.setTimeout("CountDownTick()", 1000);
}

function SetCountdownText(seconds) {
	//store:
	_currentSeconds = seconds;
	
	//get minutes:
	var minutes=parseInt(seconds/60);
	
	//shrink:
	seconds = (seconds%60);
	
	//get hours:
	var hours=parseInt(minutes/60);
	
	//shrink:
	minutes = (minutes%60);
	
	//build text:
	var strText = AddZero(hours) + ":" + AddZero(minutes) + ":" + AddZero(seconds);
	
	//apply:
	_countDowncontainer.innerHTML = strText;
}

function AddZero(num) {
	return ((num >= 0)&&(num < 10))?"0"+num:num+"";
}