Newb Button Question

programming flash
1

OK, this has to be simple, but I can’t seem to find a solution. I am generating a list of buttons (thumbnails). it’s displaying correctly. But how do I know which button I pressed on? I need to know this information so, if I press the second thumbnail it displays the correct larger image or goes to the right frame.

var btnNum:uint = 8;
var spacing:Number = 10;

var cols:Number = 3;
//x and y controllers
var ii:Number = 0;
var yax:Number = 5;

var navBar:Sprite = new Sprite();
addChild(navBar);
var btn:MovieClip;

for(var i:uint = 0; i < btnNum; i++) {
btn = new Btn();
btn.x = spacing + ii * (btn.width + spacing);
btn.y = yax;

var thumb = new Loader();
btn.addChild(thumb);
thumb.load(new URLRequest("images/thumb/1.jpg"));

btn.addEventListener(MouseEvent.CLICK, onTraceName);
btn.addEventListener(MouseEvent.ROLL_OVER , fadeMe);
btn.addEventListener(MouseEvent.ROLL_OUT , fadeOutMe);

navBar.addChild(btn);
ii++
if (ii == cols){
    yax = btn.y + (btn.height + 5);
    ii = 0;
    
}

}

var bg:MovieClip = new NavBarBack();
bg.width = cols * (btn.width + spacing);
bg.width += spacing;
bg.height = (btnNum / cols) * (btn.height + 7);
trace(btn.height);
navBar.addChildAt(bg,0);

navBar.x = (navBar.stage.stageWidth - navBar.width)/2
navBar.y = 20;

function onTraceName(EVENT){
trace(EVENT.target.name);
}

function fadeMe(EVENT){
EVENT.target.alpha = .5;
}

function fadeOutMe(EVENT){
EVENT.target.alpha = 1;
}