Mozilla developer preview (Gecko 1.9.3a1) available for download

Editor’s note: Today, Mozilla released a preview of the Gecko 1.9.3 platform for developers and testers. Check out the Mozilla Developer News announcement reposted below.

A Mozilla Developer Preview of improvements in the Gecko layout engine is now available for download. This is a pre-release version of the Gecko 1.9.3 platform, which forms the core of rich Internet applications such as Firefox. Please note that this release is intended for developers and testers only. As always, we appreciate any feedback you may have and encourage users to help us by filing bugs.

This developer preview introduces several new features, including:

and several other significant changes, including:

  • On Mac OS X, we render text using Core Text rather than ATSUI.
  • We rewrote major parts of the code for handling scrolling. See bug 526394 for details.
  • We rewrote the way a snapshot of a document is taken in order to print or print preview. See bug 487667 for details.
  • We made significant changes to table border handling. See bug 452319 and bug 43178 for details.
  • We made various architectural changes to improve Web page performance.

More information on these changes is in the release notes, as well as the Upcoming Firefox features for developers article on the Mozilla Developer Center.

Please use the following links when downloading this Mozilla Developer Preview:


Comments are now closed.

  1. James John Malcolm wrote on February 10th, 2010 at 16:43:

    It’s great that there’s a special build for Devs being promoted – but how different is this from current minefield builds, gecko-wise?

  2. Boris wrote on February 10th, 2010 at 17:19:

    James, it’s not. It’s just a minefield build that doesn’t have any obvious breakage, like any other alpha we ship.

  3. Brett Zamir wrote on February 10th, 2010 at 21:43:

    Wow, I’m SMILing now…

  4. Wes wrote on February 13th, 2010 at 09:20:

    very nice… i’m testing css transitions!

  5. Benjamin Meyer wrote on February 16th, 2010 at 23:14:

    Been working on a little css3 game that is based around transitions. Looks like FF is still missing a few thing (I never seem to get the endTransitionEvent), but getting very close. I look forward to the next release.

  6. Dan Welsh wrote on March 2nd, 2010 at 06:50:

    This is the Best Browser I have ever had the pleasure to use. My quest is over.
    Will this ever be ported for 64Bit Intel Macs? I know Josh Aas was working on one.
    Your Humble Lab Rat

  7. Pingback from Mozilla developer preview (Gecko 1.9.3a2) now available ✩ Mozilla Hacks – the Web developer blog on March 5th, 2010 at 13:30:

    […] did an a1 release about three weeks ago in order to get testing on some of the new web developer features (which […]

  8. sn123 wrote on March 13th, 2010 at 09:07:


    I am new to Gecko , I want to embed this with my J2ee application .
    Can anybody give me some idea about it , any helpful links …


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