ActionScript 3.0 :: Getting Total Number Of Images In Folder From Text File?

i have a dynamic image gallery, and what I want to do is be able to load a number that is saved in a text file and use it as the total number of images in that folder for an if statement:

this is what I have so far:

Code:
var imageNumber:Number = 1;
var loader:URLLoader = new URLLoader(new URLRequest("images/info.txt"));
loader.addEventListener(Event.COMPLETE, completeHandler);

[Code]....

how can I use the value of a variable within a function outside of that function without having to create a class and package and all that?

I need to be able to have the function return a value of a variable within itself and be able to target that value outside the function..