Javascript – How to detect TraceMonkey


Is it possible to detect that a Firefox browser is running the TraceMonkey JavaScript interpreter? If so, is it possible to do it with JavaScript? A solution which involves examining the browser binary or shared libraries is also OK for me. I'm running Linux with Firefox 3.0.14 right now.

Best Solution

  1. enter "about:config" as URL
  2. say you will be careful
  3. search "JIT"

you can check if it's enabled by looking at: -> for browser UI and plugins

javascript.options.jit.content -> for web content

(you can also change the values)

btw. if your code is a little complex don't expect to get a speed comparable to V8. Tracemonkey fails with branchy code (it may be slower than spidermonkey).

More info: