[AS3]Randomly do something without repeat

programming flash
1

Hi,

I’ve 3 movieclip on stage which is mc1,mc2,mc3
at first they are alpha=0

What I want is when i click on revealBtn, 1 of them will show up as alpha=1.

But with my code below, sometimes I need to click about 5 times or more only can make all those mc show up.

Is there any solution for what I wanted?

var mcArray:Array = [mc1,mc2,mc3];
for (var j:int = 0; j < mcArray.length; j++)
{
	mcArray[j].alpha = 0;
}

revealBtn.buttonMode = true;
revealBtn.useHandCursor = false;
revealBtn.addEventListener(MouseEvent.CLICK, revealClick);

function revealClick(event:MouseEvent):void
{
	//Generate random number (integer) between 0 and mcArray.length
	var i:Number = Math.floor(Math.random() * mcArray.length);

	//Select ith element of mcArray
	var movieClipToEdit:MovieClip = mcArray* as MovieClip;

	//Change its alpha to 1
	movieClipToEdit.alpha = 1;
}