To expand upon what Bitt said...

If you don't set the web server to explicitly deny the permission to "browse" directory listings, then you can see the contents of a web subdirectory simply by surfing to the URL of that directory. No server side coding needed.

Depending on which web server software is used on that server, it might be controlled by a hidden configuration file you place in that folder, or it might be configured some other way on the server. You might have to ask your hosting provider how to enable directory browsing on your web site.

If you do this, however, make sure not to store a file in that folder called "index.htm" or "index.html" or "index.php" something like that. Because if you do, then the web server will display that file instead of the directory listing. (And by the way, which sets of file names are counted as index pages is also something that's configured on the web server.)