Strip file name from URL

[almirr]

I want to achieve the following. From these example URLs:

http://www.domain.com
http://www.domain.com/index.php
http://www.domain.com/folder/welcome.php

I want to get:

http://www.domain.com
http://www.domain.com/
http://www.domain.com/folder/

So I want to preserver everything except the file name at the end of URL.
I know I can build this using explode, parse url, count occurences, etc. but if someone already has a worked out solution, I'd appreciate sharing.

Thanks.

[devinemke]

[man]dirname[/man]