stop();

btn1_mc.addEventListener(MouseEvent.CLICK, clicked);
btn2_mc.addEventListener(MouseEvent.CLICK, clicked);
btn3_mc.addEventListener(MouseEvent.CLICK, clicked);

function clicked(e:MouseEvent):void {
    trace(e.target.name);

    switch(e.target){
        case btn1_mc:
            gotoAndStop(1);
            break;
        case btn2_mc:
            gotoAndStop(2);
            break;
        case btn3_mc:
            gotoAndStop(3);
            break;

        }

}