By Craig Buckler

What’s New in Firefox 9.0

By Craig Buckler

Firefox 9.0 is out? Seriously? I suppose it’s been six weeks since version 8.0 was released on November 8, 2011. If you’ve not received an automatic update yet, select Help > About Firefox and hit the Check for Updates button. If all else fails, head over to and download it manually.

The add-on compatibility issue appears to have improved significantly. None of my extensions were disabled but I can’t promise you’ll have the same experience.

On the surface, little appears to have changed. Mozilla is claiming improved HTML5, CSS and MathML support. They have also published a long list of bug and security fixes to illustrate how busy they’ve been. Mac OS users may notice improved theme integration and two finger swipe navigation but, for the rest of us, the main changes are under the hood…

Improved JavaScript Performance

Mozilla are claiming a 20-30% performance boost for JavaScript in Firefox 9.0. It’s primarily been achieved using Type Inference (TI); a feature in the SpiderMonkey JavaScript engine which analyzes statements and variable values as a program executes to determine types. The information is used during JIT compilation to generate more efficient code.

It’s impressive. While I doubt you’ll experience a 30% speed increase in the wild, the early benchmarks show promise. Mozilla has certainly closed the gap on competitors, if not overtaken them.

New CSS3 font-stretch property

The new font-stretch property selects a normal, condensed, or extended face from a font family:

  • font-stretch: ultra-condensed
  • font-stretch: extra-condensed
  • font-stretch: condensed
  • font-stretch: semi-condensed
  • font-stretch: normal
  • font-stretch: semi-expanded
  • font-stretch: expanded
  • font-stretch: extra-expanded
  • font-stretch: ultra-expanded

Typefaces will only appear differently if you have a specific font type installed. Remember that many fonts don’t offer condensed or expanded types.

Improved CSS3 text-overflow Support

Firefox has supported text-overflow: ellipses since version 7 was released in September. The property shows ‘…’ at the right-most end of a text string which overflows its container.

Firefox 9.0 allows you to truncate either end of the text with a hard clip, ellipses or a custom string. For example, if “12345678” was centered in an element which was too small;

text-overflow: ',' ellipsis;

could result in “,3456…”

For more information, refer to the text-overflow reference at MDN.

A More Promising Future?

Mozilla has been losing ground to Google’s Chrome browser but Firefox 9.0 feels fast, stable and has fewer of the compatibility issues which held back earlier versions.

The organization has also announced a three-year extension to its search partnership with Google. The original deal — worth $100 million per year and 84% of Mozilla’s total revenues — ended earlier this month. Neither company has revealed the financial details; Google is certain to have renegotiated the terms, but it was hardly likely to ignore the preferred browser of one in four web users.

It’s also evident that Mozilla is trying to differentiate itself from the others — view their Firefox 9.0 video. While it’s a stomach-churning set of moralistic cliches (independently spirited people, we value values, we believe in you, etc), it’s true that Mozilla is the only browser vendor without ulterior business motives or commercial interests to protect. The web would be a lesser place without them.

If you’re considering the Firefox 9.0 update, it’s best to do so now. Firefox 10.0 is due on January 31, 2012.

  • Jack

    I wish that Firefox had a background updater like Chrome to keep low tech people always updated!

    • It is coming. In many ways, though, I prefer having the option to update or not. On slower PCs, Chrome can bring everything grinding to a halt for 10 minutes while it upgrades itself.

      • It’s not Firefox you need to update but your PC then :)

      • There is that, but I wasn’t actually referring to my PC – and you can’t force hardware upgrades on people or companies who don’t see the benefit!

  • Another informative article Craig. Thanks as always!
    For what it’s worth, I just updated and it didn’t affect any of my Plugins this time either. I haven’t minded the faster iterations with the exception of some of the Plugins failing to work after the update. Looking forward to the speed increase with the JS “performance boost”. I do hope they fixed the issue with it consuming extra system resources when left open for any length of time. It’s still my favorite browser, especially for developing in.

  • Nilay Mehta

    I have just downloaded new FF on my mac , And i like the new version!

    Not sure but Auto-update didn’t worked for me when i tried to upgrade.

    • Slobodan Ivkovic

      I had same problem, no auto update on my mac. Bug ?

      • Mozilla may be releasing the update in phases across territories and/or platforms.

      • Nilay Mehta

        Yes Right , I guess that was not a bug but a DELAY to diff territories and/or platforms.

        Because on the next morning i can able to update my FF [ My Work MAC] from Auto-updates it self.

  • I have both browsers on my PC (Firefox and Chrome) however Firefox remains the only browser I use by default, simply because it was one of the first browsers that trumpt Internet Explorer (which to this day, still remains yuk).

    The only reason Chrome has grown in popularity is the emerging broadband markets in Asia / China and that Google are simply pouring large amounts of hard currency into advertising, not specifically because Chrome is (or is not for that matter) a better browser.

    • Robby

      Chrome is okay, but one thing people never talk about is that it loads pages in a choppy fashion. I don’t care how fast/advanced it is or even if it has a unique feature or two. The bottom line for me is presentation overall, and Firefox wins. The pages load uniformly and pretty quick I might add with little retrace correction.

  • Biswa

    I am very disappointed with the new version. Every time the browser freeze and i have to wait. I love 3.6 version but most plugin is not supporting now.

  • With the way browsers are constantly speeding up their JavaScript running speed, this is becoming a very exciting time for JavaScript developers. This is one reason why I decided to make a JavaScript blog. You can check it out if you’d like:

    Right now I’m in the middle of a JavaScript Design Patterns series, but rest assured that once that’s finished, there’ll be a lot more variety and it should be a wonderful learning experience.

  • Is it usual to use a version number change for under the hood changes rather than change it to a minor version, e.g. 8.0.1 to 8.1?

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