[AS3] Change alpha property of button [from post]

programming flash
1

I am trying to change the alpha property of a button using actionscript 3.
I dont want to create external AS file. Can you guide me on this?


circle_mc.addEventListener(MouseEvent.CLICK, clickHandler);
function clickHandler(event:MouseEvent):void {
trace("You clicked the ball");
 //circle_mc.startDrag();
//square_btn.visible=false;
//what should i write to change the alpha of square_btn?
 
}