How can you execute a function while the mouse is over a button.

Question

I've got a movieclip I want to move across the screen on the x axis to the left or right depending on which button the user hovers their mouse over.
I thought I could do this with the following:
right_btn.addEventListener(MouseEvent.MOUSE_OVER, moveRight);
left_btn.addEventListener(MouseEvent.MOUSE_OVER, moveLeft);
function moveRight(e.MouseEvent):void
     sampleMovieclip_mc.x += 1;
function moveLeft(e.MouseEvent):void
     sampleMovieclip_mc.x -= 1;
But I find that it only moves it 1 pixel when the mouse first goes over the button and not continiously as it stays over it.  I tried using Event.ENTER_FRAME to call the moveRight and moveLeft functions, but it just keeps going and I'm not sure how to kill the function once they move the mouse off of the button.
Any help would be greatly appreciated.
Thanks.

Answer 1

use removeEventListener() method. Here is one of the ways to deal with it:
// move direction
var xd:int = 1;
// speed along x
var xs:Number = 1;
right_btn.addEventListener(MouseEvent.MOUSE_OVER, onMouseOver);
right_btn.addEventListener(MouseEvent.MOUSE_OUT, onMouseOut);
left_btn.addEventListener(MouseEvent.MOUSE_OVER, onMouseOver);
left_btn.addEventListener(MouseEvent.MOUSE_OUT, onMouseOut);
function onMouseOver(e:MouseEvent):void {
     xd = e.curretnTarget == right_btn ? 1 : -1;
     addEventListener(Event.ENTER_FRAME, onEnterFrame);
function onMouseOut(e:MouseEvent):void {
     removeEventListener(Event.ENTER_FRAME, onEnterFrame);
function onEnterFrame(e:Event):void
     sampleMovieclip_mc.x += xd * xs;