Firefox 3.1: How to Enable the TraceMonkey JavaScript Engine

Contributor Icon Contributed by shamanstears Date Icon October 14, 2008  
Tag Icon Tagged: Mozilla Firefox

TraceMonkey is the magic pill that makes the new Firefox much quicker. Unfortunately, the beta version has this feature disabled. By changing the value of a couple of configuration settings, you can easily enable TraceMonkey and enjoy its speedy goodness.

1. Open Firefox.

2. In the Location Bar, input about:config.

3. Click to get past the warning message that appears.

4. Locate the Preference Name javascript.options.jit.chrome.

5. Double-click the preference and change the value to true.

6. Locate the Preference Name javascript.options.jit.content.

7. Double-click the preference and change the value to true.

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  • fastfreddie1959
    Locate the Preference Name javascript.options.jit.chrome.
    Locate the Preference Name javascript.options.jit.content.

    Neither key exsists in FF 3.1
  • Actually, they do. Go to about:config and input the word javascript into the filter. They will be the 4th and 5th preferences listed.
  • pearlworm
    Locate the Preference Name javascript.options.jit.chrome.
    Locate the Preference Name javascript.options.jit.content.

    Nope! still not in my version 3.03
  • nanda
    they won't be in 3.03, this is about 3.1
  • adi
    its a tweak for firefox Minefield, not 3.03
  • pearlworm
    Okay, downloaded Minefield and found them Thanks
  • caffino
    how do you download minefield
    i looked and nothing showed up
  • kansei
    it's called google. Try "download minefield" it's all over the first results
  • Geoff
    Fantabulous feature! Tnx a $M
  • dorai
    it is good i done it very easily
  • Trikkk
    do you have any technical details or an link about how is this change of speed happening ? I mean, I have enabled both options(the truth is that in 3.1b2pre ----- Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b2pre) Gecko/20081107 Minefield/3.1b2pre, the option:'javascript.options.jit.content.' is already enabled by default, so just enabled the "....chrome" .I have already seen an important increase at speed, but I need to know how it is achieved.I mean, where's the catch?
  • Kris
    Google JIT or Tracemonkey

    There is no catch
  • Mallikarjun
    FF is not troubling me now .............Thanks
  • Ross
    Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2a1pre) Gecko/20081208 Minefield/3.2a1pre

    This doesn't seem to make a difference for me, tested using sunspider javascript benchmark.
  • 8. If things break, remember what you did in #3.
  • Minefield Rocks!
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