Performance-measuring tools

Finally, there are a number of useful tools for measuring JavaScript performance. Conveniently, the original author of Three.js has written a library called Stats.js (https://github.com/mrdoob/stats.js) for tracking frame rates, the most crucial performance statistic for games. For comprehensive tracing, Google's Web Tracing Framework (http://google.github.io/tracing-framework/index.html) is hard to beat, and it even has an example for tracing a WebGL game. You can also easily get some statistics about onscreen geometry with the RenderStats library from Jerome Etienne (https://github.com/jeromeetienne/threex.rendererstats).

For brute-force debugging, you may also want to try the console-extras library, which makes it easier to log information about things that happen in the main game loop without dumping thousands of messages (https://github.com/unconed/console-extras.js).