I was recently looking around for some examples in Javascript for an isometric proof-of-concept I'm working on, when I came upon Crafty.js">. It had some neat demos, and it was MIT licensed, so I got to work - and I was pleasantly surprised by the library. The documentation itself is a little lacking- and its official tutorial (at the time of this post) was using an outdated version of the library (which has had several breaking changes), but I managed to come across an excellent tutorial by "Starmelt" on GitHub that takes you through the process of building a simple game in Crafty. It introduces you to entity creation, the game loop, the eventing structure, and more - and once you're done, it's easy to add on to (for example, I kept a global high scores list, and added a "reset" button.)

Also, Crafty includes an isometric demo, which works once you replace "Crafty.isometric.init" with "Crafty.isometric.size" in the source code.

I recommend playing around with the code - it's very lean and flexible. It's definitely worth checking out if you're looking for a springboard into JS game development. Here's a few notes:

• Switch between canvas and DOM with no code changes (besides telling it which to render in)
• Claims to support IE6+
• Easily extensible - build entities using interface-like structures
• Seemed fast in the demos I was trying
• Handles animations through tweening over the game loop (you can set the fps)
• Mouse  and keyboard events
• Collision detection, dragging API
• Hard-to-find documentation on available events and modules (it's possible that I'm blind, and am looking right past it, too)
• MIT license
• Excellent tutorial by Starmelt