Suggestion please, return value

programming flash
1 

var slidesX:XML;
var picList:XMLList;

var testS:String = "var";

var loader:URLLoader = new URLLoader();
loader.addEventListener(Event.COMPLETE, onComplete);
loader.load(new URLRequest("xml-swf-images.xml"));

function onComplete(e:Event):String
{
    slidesX = new XML(loader.data);
    picList = slidesX.image;
    trace(picList[1]);
    trace(picList[1].src.text());
    trace(picList[1].src.toString());
    testS = picList[1].src.toString();
    trace("Test " + testS);
    return testS;
}

    trace("TestOUT " + testS);

so i am trying to return value from onComplete function so that i can use use it in what ever way, but that aint happening : ( what am i doing wrong?

thank you