AS3 Make a Movieclip vanish when left alone for a certain duration

Question

Original Edit I am wanting to know the best method for a making a movieClip fade way on the stage. I can guess how to do it in as2 (that's what I was taught in) but I'm unsure how to to develop my code below. As a guess I would assume to attach it to an enterFrame event.

Basically, over the course of 5 seconds if the user hasn't interacted with the balloon, it fades to nothing using alpha.

Any pointers or suggestions? I'm new to AS3. (please ignore the CLICK)

reset_balloon.addEventListener(MouseEvent.CLICK, fadeBalloon);
 function fadeBalloon(event:MouseEvent):void 
 { 
    reset_balloon.alpha = .2; 
 } 

Secondary Edit -----

//---- 
//Resetter btn ---------------------
//------------------------------------------

reset_btn.addEventListener(MouseEvent.CLICK, startover);

 function startover(event:MouseEvent):void
  {
   //gotoAndPlay(2);
   reset_balloon.visible = true;
  }

  //---- 
Object(root).reset_balloon.thereseter_btn.addEventListener(MouseEvent.CLICK, truestartover);

  function truestartover(event:MouseEvent):void
  {
     gotoAndPlay(2);
   //reset_balloon.visible = false;
  }


  TweenLite.delayedCall(5, handleTimeUp)

   function handleTimeUp():void
   {
    TweenLite.to(reset_balloon, 2, {alpha:0});
   }

   reset_balloon.addEventListener(MouseEvent.CLICK, fadeBalloon);

    function fadeBalloon(event:MouseEvent):void 
     { 
     //reset_balloon.alpha = .5; 
  TweenLite.killDelayedCallsTo(handleTimeUp);
  TweenLite.to(reset_balloon, 2, {alpha:0.4});
    }

Answer 1

If you don't mind using Tweens, I'd recommend TweenLite for this one.

//Add function called in 5 secs
TweenLite.delayedCall(5, handleTimeUp)

private function handleTimeUp():void
{
    TweenLite.to(reset_balloon, 2, {alpha:0});
}

And if for some reason you want to kill pending delay call (for example on mouse click);

reset_balloon.addEventListener(MouseEvent.CLICK, fadeBalloon);
private function fadeBalloon(event:MouseEvent):void
{
    TweenLite.killDelayedCallsTo(handleTimeUp);
}