This snippet allows create a countdown for milliseconds usefull for games. It must be included into a movieclip which contains a dynamic text field called 'tf'.

CountdownTimer.as

import com.greensock.TweenMax;

var now:Date;
var endDate:Date;
var seconds:Number;
var isRunning:Boolean;
var wasInitialized:Boolean;

function updateTime(e:Event):void {
	var currentDate:Date = new Date();
    var timeLeft:Number = endDate.getTime() - currentDate.getTime();
    var milliseconds:Number = timeLeft;  
	var newSeconds:Number = Math.floor(timeLeft / 1000);
    
	if (seconds != newSeconds && seconds > 0 && seconds <= 6) {
		// Poner sonido de terror aquí
		TweenMax.to(tf, 0, {textColor:0xff0000});
		TweenMax.to(tf, 0, {textColor:0xffffff, delay:0.5});
	}
	
	seconds = Math.floor(timeLeft / 1000);
	
	milliseconds %= 1000;
    seconds %= 60;
    
    var ms:String = milliseconds.toString().substr(0, 2);
	//var ms:String = Math.round(milliseconds/10).toString();
    var sec:String = seconds.toString();
    
	if (sec.length < 2) {
        sec = "0" + sec;
    }
	
    var time:String = sec + "." + ms;
    tf.text = time;

	if (seconds < 0) {
		removeEventListener(Event.ENTER_FRAME, updateTime);
		setText("00.00");
		wasInitialized = false;
		trace("Finished!");
    }
}

function startTimerFrom(endSeconds:int) {
	stopTimer();
	isRunning = true;
	wasInitialized = true;
	now = new Date();
	endDate = new Date(now.fullYear, now.month, now.date, now.hours, now.minutes, now.seconds + endSeconds);
	addEventListener(Event.ENTER_FRAME, updateTime);
}

function resumeTimer() {
	if (wasInitialized) {
		isRunning = true;
		addEventListener(Event.ENTER_FRAME, updateTime);
	}
}

function stopTimer() {
	isRunning = false;
	removeEventListener(Event.ENTER_FRAME, updateTime);
}

function addSecondsToTimer(seconds:int) {
	stopTimer();
	endDate = new Date(endDate.fullYear, endDate.month, endDate.date, endDate.hours, endDate.minutes, endDate.seconds + seconds);
	resumeTimer();
}

function setText(text:String) {
	tf.text = text;
}

//startTimerFrom(30);

Require:

• TweenMax
• Flash Timeline based project