flash (macromedia): Hello

I'm having terrible problems with my preloader, I can't even get started with
this one until I get some basics. Here is my code so far:


I thought that the progressHandler() would be called 20 times per second,
since I made my document to work by that FPS. I guess that's not the case,
since my code only prints my loaded status once. So what do I need to do in
order to get the currently loaded bytes, so I can use those values in my
preloader bar. Is there any universal (=better) way to code a preloader in
Actionscript 3.0?



import flash.display.Sprite;
import flash.events.*;
import flash.net.*;

var loader:URLLoader = new URLLoader();
configureListeners(loader);

var request:URLRequest = new URLRequest("My_Site.swf");
try {
loader.load(request);
} catch (error:Error) {
trace("Unable to load requested document.");
}


function configureListeners(dispatcher:IEventDispatcher):void {
dispatcher.addEventListener(Event.COMPLETE, completeHandler);
dispatcher.addEventListener(Event.OPEN, openHandler);
dispatcher.addEventListener(ProgressEvent.PROGRESS, progressHandler);
}

function completeHandler(event:Event):void {
trace("FINISHED");
}

function openHandler(event:Event):void {
trace("openHandler: " + event);
}

function progressHandler(event:ProgressEvent):void {
trace("progressHandler loaded:" + event.bytesLoaded + " total: " +
event.bytesTotal);
}