ActionScript 3.0 :: Making Buttons To Link With URL?

Im trying to make two buttons for my artefact to link to facebook and twitter, but it doesn't work. I've got no error messages or anything, I just click the button and it doesn't do anything

The code is the following:
BTN_FACEBOOK.addEventListener(MouseEvent.CLICK, FacebookClick);
function FacebookClick(event:MouseEvent):void{
var getFacebook:URLRequest = new URLRequest("[URL]");
navigateToURL(getFacebook);
}

BTN_TWITTER.addEventListener(MouseEvent.CLICK, TwitterClick);
function TwitterClick(event:MouseEvent):void{
var getTwitter:URLRequest = new URLRequest("[URL]");
navigateToURL(getTwitter);
}