How do I use this URLRequest script? - actionscript-3

Question

I started learning ActionScript 3 a week ago and have stumbled across a huge learning curve. I found this script on the internet:
var _loader:URLLoader;
var _request:URLRequest;
function loadData():void {
_loader = new URLLoader();
_request = new URLRequest("http://www.travoid.com/game/Purchase.php?gid=1");
_request.method = URLRequestMethod.POST;
_loader.addEventListener(Event.COMPLETE, onLoadData);
_loader.addEventListener(IOErrorEvent.IO_ERROR, onDataFailedToLoad);
_loader.addEventListener(IOErrorEvent.NETWORK_ERROR, onDataFailedToLoad);
_loader.addEventListener(IOErrorEvent.VERIFY_ERROR, onDataFailedToLoad);
_loader.addEventListener(IOErrorEvent.DISK_ERROR, onDataFailedToLoad);
_loader.load(_request);
}
function onLoadData(e:Event):void {
trace("onLoadData",e.target.data);
}
function onDataFailedToLoad(e:IOErrorEvent):void {
trace("onDataFailedToLoad:",e.text);
}
This all seems to work and is generating no errors or output, however my issue comes about when I use this next part of code (which I made)
function vpBuy(e:MouseEvent):void{
loadData();
if (e.target.data == "false") {
inf_a.visible = true;
inf_b.visible = true;
inf_c.visible = true;
inf_d.visible = true;
btn_ok.visible = true;
}
}
I get this error:
ReferenceError: Error #1069: Property data not found on
flash.display.SimpleButton and there is no default value. at
travoid_fla::MainTimeline/vpBuy() onLoadData
The part that is probably throwing this is:
if (e.target.data == "false") {
I was hoping e.target.data was what stored the value on the web page (which displays as false) but apparently not. With the code I found on the internet, what stores the information on the web page?
Thanks,
Ethan Webster.

Answer 1

The URLLoader load method is asynchronous, you have to wait the server response before triyng to get the result.
The functions onLoadData and onDataFailedToLoad are there to do that. When the response is well received the function onLoadData is called and you can get the data in e.target.data or _loader.data
The error in your function vpBuy is you try to access the data property on the object that triggered the MouseEvent (maybe a Button) and that object don't have such variable.
Try the following:
/** button clicked load the datas from the server **/
function vpBuy(e:MouseEvent):void
{
// load the datas from the server
loadData();
}
/** the datas are well loaded i can access them **/
function onLoadData(e:Event):void
{
trace("onLoadData",e.target.data);
if( e.target.data == "false" )
{
inf_a.visible = true;
inf_b.visible = true;
inf_c.visible = true;
inf_d.visible = true;
btn_ok.visible = true;
}
}
Hope this could help you :)