Is this a correct way to capture keys?

programming flash
1

Dear all,

I want to capture when arrow up and arrow down are pressed. The idea is while these keys are pressed I will move a movieClip. This is what I did:

stage.addEventListener(KeyboardEvent.KEY_UP,key_Up);
stage.addEventListener(KeyboardEvent.KEY_DOWN,key_Down);
stage.addEventListener(Event.ENTER_FRAME,mainLoop);

function key_Up(event:KeyboardEvent) {
	keyPressed=-1;
}

function key_Down(event:KeyboardEvent) {
	keyPressed = event.keyCode;
}

function mainLoop(event:Event) {
	if (keyPressed ==38) {
		trace("ArrowUp")
	}
	if (keyPressed==40) {
		trace("ArrowDown")
	}
}

Thanks in advance for feedback