Following Java (on Android) and C++ (on Windows), I just released my first Javascript sources over at my bitbucket repository. My first (ever) public JavaScript demo is the random dungeon generator that I wrote an article about (a long time ago).
It generates random dungeons of different sizes and can be tested directly in your browser over here. Included are the JavaScript sources for the random dungeon generator that use HTML5 for drawing a simple representation of the randomly generated rooms and corridors.
My plan now is to add some more randomness, some game-related features and to write a WebGL-renderer, so you can walk the dungeons in your browser, with maybe a game to follow.