Any sort of PHP script that searches directory for names of files? [on hold]

I am trying to get a sort of search engine type thing that searches for names of files based on what a user posts, and then displays all related searches+links to them.

I have tried this:

var str = "";
var n = search("files/"); 

And I have no idea how JavaScript works. I want some sort of PHP script to do this.

Please, no database if possible (but i can deal with it).