How do I get the Interval to keep from repeating after it's used once?

Question

How do I get the Interval to keep from repeating after it's used once? Because I tried clearInterval but I couldn't get it working.
When my code looks like this, with ClearInterval, it refuses to execute my action, which is to change scenes after a short interval:
(Pardon if there is some formating errors, I had to reformat it for the Internet)
Code with clearInterval command
stop(); 
Kollektiv.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndPlayFromFrame_2);
function fl_ClickToGoToAndPlayFromFrame_2(event:MouseEvent):void{
   gotoAndPlay(29);   
   var myInterval:uint = setInterval(fl_ClickToGoToNextScene_14,3000);   
   clearInterval(myInterval);
function fl_ClickToGoToScene_14(event:MouseEvent):void{
    MovieClip(this.root).gotoAndPlay(1, "Testside");
However, when my code looks like this it refuses to stop looping:
Code without ClearInterval command
stop();
Kollektiv.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndPlayFromFrame_2);
   function fl_ClickToGoToAndPlayFromFrame_2(event:MouseEvent):void{
   gotoAndPlay(29);
   setInterval(fl_ClickToGoToNextScene_14,3000);
function fl_ClickToGoToScene_14(event:MouseEvent):void{
    MovieClip(this.root).gotoAndPlay(1, "Testside");
Any ideas? Also, feel free to dumb your answer down, because I am completely new to Flash, Actionscript and coding.

Answer 1

If you insist on using setInterval - you need to declare interval id in a higher scope so that you can clear it later:
stop();
var myInterval:uint;
Kollektiv.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndPlayFromFrame_2);
function fl_ClickToGoToAndPlayFromFrame_2(event:MouseEvent):void
          gotoAndPlay(29);
          myInterval = setInterval(fl_ClickToGoToNextScene_14, 3000);
function fl_ClickToGoToScene_14():void
          clearInterval(myInterval);
          MovieClip(this.root).gotoAndPlay(1, "Testside");
I suggest you use Timer instead:
stop();
import flash.events.TimerEvent;
import flash.utils.Timer;
var timer:Timer = new Timer(3000, 1);
timer.addEventListener(TimerEvent.TIMER, fl_ClickToGoToScene_14);
function fl_ClickToGoToAndPlayFromFrame_2(event:MouseEvent):void
          timer.start();
          gotoAndPlay(29);
function fl_ClickToGoToScene_14(event:TimerEvent):void
          timer.stop();
          MovieClip(this.root).gotoAndPlay(1, "Testside");