Selenium is a Javsscript game framework built for creating isometric pixelart games in the browser. It was built expressly for the Khaal RTS game, and as such has many elements that help specifically with RTS/city builder game development.
Selenium is built to be a braindead-framework. All the WebGL (beyond out-of-scope shaders) is abstracted away, and in its place easy-to-understand interfaces remain. All you need to properly use the framework is a configured project and a copy of Selenium. For setup details, check out the wiki.
Found a bug or missing feature? Make a pull request or issue! However, be sure your code follows the contribution guidelines.