Enumerate File List In FireFox

I'm working on a DHTML Client side app (runs on the local system) which needs to query a list of files in a particular directory. I know how to read files in from the local files system. And i found what i think is the relevent code from the Mozilla Development Center, however...i'm uncertain how to put the code together. One of my goals is to write a File-Manager in DHTML which can be used on the local file system :) Moz Dev page: [URL] here's the code snipped for reading in a list of files:

// file is the given directory (nsIFile)
var entries = file.directoryEntries;
var array = [];
while(entries.hasMoreElements())
{
var entry = entries.getNext();
[Code]....