Gladiator 3D was written by Matthias Ladkau.
Creating pseudo 3D games with HTML 5 canvas and raycasting tutorial by Jacob Seidelin http://dev.opera.com/articles/view/creating-pseudo-3d-games-with-html-5-can-1/
Ray-Casting Tutorial For Game Development And Other Purposes by F. Permadi http://www.permadi.com/tutorial/raycast/index.html
Lode's Raycasting Tutorial by Lode Vandevenne http://lodev.org/cgtutor/index.html
Gladiator 3D is released under the MIT license.
How to use
Best take a look in the example folder. There is a simple demo which demonstrates the basic concepts. And there is a more complex game demo which shows a playable game with all of the main mechanics working.