Importation de variable contenant des URL

import fl.controls.Button;
import flash.events.MouseEvent;
import flash.net.URLRequest;
import flash.net.URLLoader;
import flash.events.Event;
import flash.net.navigateToURL;

var urlPdf:String;
var bouton_btn:Button;
bouton_btn.label = "Charger l'XML";
bouton_btn.addEventListener(MouseEvent.CLICK, openPDF);

function openPDF(event:MouseEvent):void {
	if (urlPdf == null) {
		loadXML();
	} else {
		var rq:URLRequest = new URLRequest(urlPdf);
		navigateToURL(rq,"_blank");
	}
}

function loadXML():void {
	var rq:URLRequest = new URLRequest("http://www.mon.site.com/xml.xml");
	var ld:URLLoader = new URLLoader();
	ld.addEventListener(Event.COMPLETE, onLoadXML);
	ld.load(rq);
}
function onLoadXML(event:Event):void {
	bouton_btn.label = "Ouvrir le PDF";
	var ld:URLLoader = event.currentTarget as URLLoader;
	ld.removeEventListener(event.type, onLoadXML);
	var xml:XML = new XML(ld.data);
	urlPdf = xml.url.text().toString();
}