Help in AS3 code of 24 hour countdown timer

Question

hello,
i  just wanna ask if someone can help me,
i created a 24 hour flash countdown timer here http://allofmyworks.weebly.com/flash.html
the problem is when it reaches the desired time, the time still counts and became negative,
what i want is to make it only 24hour countdown clock and when it reaches the time it will only stay in 00:00:00
thanks
here is the code i used
var endDate:Date = new Date(2012,0,4);
var countdownTimer:Timer = new Timer(1000);
countdownTimer.addEventListener(TimerEvent.TIMER, updateTime);
countdownTimer.start();
function updateTime(e:TimerEvent):void
          var now:Date = new Date();
          var timeLeft:Number = endDate.getTime() - now.getTime();
          var seconds:Number = Math.floor(timeLeft / 1000);
          var minutes:Number = Math.floor(seconds / 60);
          var hours:Number = Math.floor(minutes / 60);
          seconds %= 60;
          minutes %= 60;
          var sec:String = seconds.toString();
          var min:String = minutes.toString();
          var hrs:String = hours.toString();
          if (sec.length < 2) {
                    sec = "0" + sec;
          if (min.length < 2) {
                    min = "0" + min;
          if (hrs.length < 2) {
                    hrs = "0" + hrs;
          var time:String = hrs + ":" + min + ":" + sec;
          time_txt.text = time;

Answer 1

here is the code
var endDate:Date = new Date(new Date().getTime()+24*60*60*1000);
var countdownTimer:Timer = new Timer(1000);
countdownTimer.addEventListener(TimerEvent.TIMER, updateTime);
countdownTimer.start();
function updateTime(e:TimerEvent):void
          var now:Date = new Date();
          var timeLeft:Number = endDate.getTime() - now.getTime();
          var seconds:Number = Math.floor(timeLeft / 1000);
          var minutes:Number = Math.floor(seconds / 60);
          var hours:Number = Math.floor(minutes / 60);
          seconds %= 60;
          minutes %= 60;
          var sec:String = seconds.toString();
          var min:String = minutes.toString();
          var hrs:String = hours.toString();
          if (sec.length < 2) {
                    sec = "0" + sec;
          if (min.length < 2) {
                    min = "0" + min;
          if (hrs.length < 2) {
                    hrs = "0" + hrs;
          var time:String = hrs + ":" + min + ":" + sec;
          time_txt.text = time;