With many web applications becoming more dependent on JavaScript, much work is being put into improving JavaScript performance. Even though Google’s Chrome uses WebKit (the same engine as Safari), they’re using a different JavaScript engine named V8. Mozilla will be using TraceMonkey in Firefox 3.1, and Safari will be using SquirrelFish Extreme.

All these engines compile down to native code.  How much does this affect performance? Taking WebKit as an example, the original SquirrelFish is about 50% faster than Safari 3.1’s JavaScript engine (already 3x the speed of Safari 3.0). Adding native code compilation, as well as other speedups (including a regular expression just-in-time compiler) makes SquirrelFish Extreme more than twice as fast as SquirrelFish.

The engines are playing leap frog, and all seem to be in very active development, so I find it very interesting to follow. I’ve found that SquirrelFish (Moderate, haven’t tried Extreme) works quite well, and I’ve played a few minutes with Chrome and found that to work well, too.

Exciting times in the JavaScript world.