(as3) Bouton addEventListener (MouseEvent)

import flash.display.Sprite;
import flash.events.MouseEvent;
import flash.net.navigateToURL;
import flash.net.URLRequest;

var monBtn:Sprite = new Sprite();
monBtn.graphics.beginFill(0x000000,1);
monBtn.graphics.drawRect(100,100,80,30);
monBtn.graphics.endFill();
addChild(monBtn);
monBtn.buttonMode = true;
monBtn.addEventListener(MouseEvent.MOUSE_OVER,over);
monBtn.addEventListener(MouseEvent.MOUSE_OUT,out);
monBtn.addEventListener(MouseEvent.MOUSE_DOWN,down);

function over(me:MouseEvent):void{
 me.currentTarget.alpha = 0.8;
 }
function out(me:MouseEvent):void{
 me.currentTarget.alpha = 1;
 }
function down(me:MouseEvent):void{
 trace("Down ok");
 navigateToURL(new URLRequest("http://actionscript-3-flash.blogspot.com"));
 }