If you are interesting in making games in HTML5, you will want to take a peek at Tiny Platformer. Not only is one level of pure bliss, but the author goes over the methods for making the game with code examples. He uses the Tiled editor to make the level and then explains how he wrote the JavaScript and used the HTML5 Canvas element to make the game.

http://codeincomplete.com/posts/2013/5/27/tiny_platformer/