Graded Browser Support: Updated A-Grade Chart

By YUI TeamFebruary 19th, 2008

This post marks the first Graded Browser Support (GBS) update of 2008. It modifies the A-Grade support chart and offers a forecast of likely future changes. The current A-Grade support chart is always on the YUI web site; updates are always announced here.

There are three main changes in this update:

  • Safari 3 begins receiving A-Grade support on Mac 10.4 and 10.5
  • Safari 2 stops receiving A-Grade support.
  • Firefox 1.5 stops receiving A-Grade support.

Current A-Grade Support Chart

Win 98 Win 2000 Win XP Win Vista Mac 10.4 Mac 10.5
IE 7.0 A-grade A-grade
IE 6.0 A-grade A-grade A-grade
Firefox 2.0.† A-grade A-grade A-grade A-grade A-grade A-grade
Opera 9.† A-grade A-grade A-grade A-grade A-grade
Safari 3.0† A-grade A-grade

The dagger symbol (as in “Firefox 2.0.†”) indicates that “the latest single non-beta version at that branch level” receives support. Read it as “the most recent” instead of “all” but note that 2.1.0 would not be included because it’s not at “that branch level.”

GBS Forecast

In addition to the effective-immediately changes, we’re also keeping our eyes on some pending developments.

  • Firefox 3 and Internet Explorer 8

    GBS does not extend A-Grade support to beta versions of browsers. (They receive X-Grade support by definition.) However, it’s important to be aware of forthcoming releases, especially from established brands that enjoy rapid adoption once generally available (GA). We are currently watching the development progress of Firefox 3 and Internet Explorer 8.

    We made an exception to our “no betas” stance during IE7’s beta phase in recognition of IE’s market share and ability to promote rapid adoption. These exceptions — committing development and QA resources to provide A-Grade support prior to a GA release — give us an opportunity to learn the new browser’s quirks and provide feedback while it is still being developed. And it means our sites are prepared when it does reach GA. We will likely extend the same accommodation to IE8. Stay tuned.

  • Windows 98

    We anticipate that in the next GBS update we will discontinue A-Grade support for browsers running on Windows 98.

Other Notes

  • YUI 2.5.0, released earlier this week, still provides A-Grade support to Safari 2. It’s unlikely that future YUI release will. For now: bonus browser support!

  • We are going to begin archiving these individual updates more than we’ve done in the past. We’ve heard your request to have snapshots of the GBS chart at a particular moment in time. We plan to publish these detailed updates on this blog, and collect the links to the various updates in a new Archive section of the web site.

  • Currently browsers receiving A-Grade support are the only ones enumerated in chart form. I’ve heard your requests to see the other charts, and I’d sincerely hoped to have those ready to share by now. Unfortunately, some associated tools are not yet complete. But I’m working on it!


  1. Great work Nate – already added this as a Web Clip on my Dashboard. Can’t wait to see a lot of those O/S’s and browsers (ahem….IE6…cough….Win 98 disappear from that list.

    Any word yet on when updates to the chart can be expected? Perhaps when new browsers come out or by quarter like last time? Just curious.

    Thanks again for the great work.

  2. Administrator said:
    February 22, 2008 at 2:42 pm

    Hey James,

    We’re not committing to a strict quarterly release schedule, but we’ll certainly have more updates than we did last year.

    Thanks for the feedback.

  3. I was very happy to see Safari 2 come off your support chart…. so happy, I felt obliged to blog about – and I am the most infrequent of bloggers!

    I use the YUI A-Grade Chart to help draw a cut-off point for the browsers I support in my web design projects… and frankly, I’ve been wondering when you were going to update to Safari 3.

    Ever since Safari 3 was released, I kept hinting to clients and colleagues that we could let support for Safari 2 slide b/c Mac users are fast to upgrade. But I didn’t feel comfortable really sticking to that declaration… until now.

    More on those thoughts

  4. Gaah! Don’t support browsers: support rendering engines! It’s so frustrating that SeaMonkey and Camino and Flock and all other Gecko based browsers like that, which have _exactly_ the same capabilities as Firefox, continuously get ignored and actively shut out.
    Gecko is Gecko!

  5. Bart,

    GBS does not “shut out.” Graded Browser Support provides X-Grade support to Camino, Flock, and SeaMonkey, as well as Maxthon, Bento, IceWeasel, K-Meleon, iCab, Konqueror, Shiira and over 10,000 others.

    As the GBS documentation points out, “The only practical difference between A and X-grade browsers is that QA actively tests against A-grade browsers.” I believe this is the right approach because it allows us to serve the full experience to all non-C-grade browsers while still conducting structured and rigorous QA testing.

    As I wrote at the start of GBS’s definition, “in modern web development we must support all browsers. Choosing to exclude a segment of users is inappropriate, and, with a ‘Graded Browser Support’ strategy, unnecessary.” Based on your comment, I suspect you agree.

    I welcome any feedback you have on the full GBS strategy.


    Thanks for the blog post and the comment!


  6. Do you have any information as to what level of support YUI receives on Ubuntu/FireFox 2.0.x?

  7. Administrator said:
    March 4, 2008 at 9:55 am


    That is a good example of a browser that receives X-Grade support.


  8. David-Sarah Hopwood said:
    March 17, 2008 at 12:45 pm

    The lack of A-grade support for *any* browser on any non-Mac Unix is bizarre. For example, a Gecko-based browser can’t be assumed to behave in precisely the same way on Linux as it does on Windows and Mac, or even closely enough to avoid testing.

  9. Hey David-Sarah Hopwood,

    The concept of A-Grade Support is predicated on trust. Perhaps the most important part of the definition of A-Grade support is that our developers and testers “actively test against A-grade browsers.”[1] Put another way, part of the value of GBS is that it “enables meaningful, targeted, and cost-effective QA testing.” [2]

    Each new combination of browser/platform that receives A-Grade support is expensive because it requires time and materials to test, and development time to support.

    The decision to offer A-Grade support is based on many factors concrete and abstract.

    Lack of A-Grade support does not indicate anything about a browser (other than that it does not enjoy A-Grade support). To conclude that Browser Foo and Browser Bar render “closely enough to avoid testing” because Browser Foo receives A-Grade support is not valid.



  10. Quick clarification: By trust I mean that followers of GBS are trusted to test on all A-Grade platforms. Therefore GBS strengthens itself when it makes A-Grade testing more feasible, and weakens itself when it makes A-Grade testing less feasible (and/or likely).

    Striking this balance is one of many factors in determining the A-Grade membership.

  11. Samuel Cochran said:
    July 3, 2008 at 12:30 am

    How long until we see Firefox 3 and Safari 3.1 for Windows on this list?