Graded Browser Support: Q4 Update

By YUI TeamNovember 15th, 2006

Approximately every three months we update the chart detailing which browsers receive A-grade support according to Graded Browser Support. In conjunction with yesterday’s YUI update release, here is our browser support update for Q4 2006.

In summary: A-grade support begins for Firefox 2.0, and is reiterated for IE7. A-grade support is discontinued for IE 5.5 and Firefox 1.0. Seldom-used Gecko derivatives (e.g., Netscape and Mozilla Application Suite) now receive X-grade instead of A-grade support. Opera 9 now receives A-grade support on additional platforms.

In bullet form, here are all the changes in this update:

  1. Reiteration of A-grade support, IE 7, Win(XP)
  2. Termination of A-grade Support, IE5.5, Win
  3. Initiation of A-grade Support, Firefox 2.x, Win/Mac.
  4. Termination of A-grade Support, Firefox 1.0.x, Win/Mac.
  5. Expansion of A-grade support, Opera 9.x, Win/Mac
  6. Termination of A-grade support, Mozilla App Suite, Win/Mac
  7. Termination of A-grade support, Netscape, Win/Mac

Though you should always reference the official GBS chart hosted on the Yahoo! Developer Network, I’ve included a snapshot of this quarter’s chart for posterity’s sake:

Win 98 Win 2000 Win XP Mac 10.3.x Mac 10.4
IE 7.0 A-grade
IE 6.0 A-grade A-grade A-grade
Firefox 2.0.* A-grade A-grade A-grade A-grade A-grade
Firefox 1.5.* A-grade A-grade A-grade A-grade A-grade
Opera 9.* A-grade A-grade A-grade A-grade A-grade
Safari 2.0* A-grade

Looking ahead to next quarter (2007Q1), we will reflect incremental releases of supported browsers but no major changes are anticipated.



  1. Yahoo! UIの対応ブラウザ…

    Yahoo! より配布されている「Yahoo! UI」の対応ブラウザが、変更になります。
    Internet Explorer、Firefoxの2大ブラウザのメジャーバージョンアップ版「IE 7」「Firefox 2」が含まれたものになってい……

  2. Where is the full chart?? Where is the chart that also shows C grade and X grade browsers?

    Please, add that information back into your chart, instead of showing only A grade browsers.

  3. Peter van Kampen said:
    November 15, 2006 at 11:58 am

    What do the *’s signify?

    Is there no *nix support at all?

  4. This is excellent news guys. Any chance to see support for Opera 7.1 on Ubuntu Linux? (I kid, I kid)

  5. [...] Joseph sent around this chart of Yahoo’s updated browser support chart. [...]

  6. @Peter: The “*”‘s represent “all” or “any.” And depending where they fall, they could be either a minor or patch release by the particular browser vendor. The typical representation of a version is major.minor.patch: Eg: v 1.0.0

    You can then interpret the table as so:

    Grade A support is provided for “all” Firefox 2.0 patch releases.

    Grade A support is provided for “all” Opera 9 minor releases. etc. etc…

  7. @Jeff: It’s important for us to provide an A-grade chart to communicate which browsers we comprehensively test on. I agree that providing a C-grade chart would be helpful because by definition those are the browsers we recommend withholding CSS and JS from. (We don’t test on each and every C-grade browser; spot testing the functionality of the core markup is sufficient.)

    There won’t be an X-grade chart because by definition X-grade is “everything else” (we see over 10,000 user agents/month!).

    @Peter van Kampen: We expect that *nix flavors of Gecko and other standards-friendly rendering engines will have an excellent experience. I think this illustrates the benefit of our “X-grade support” concept.


  8. Why does Netscape have been moved to X-grade, still there are some big communities of users are there for Netscape!

    BTW, checkout some of my usability study about the Flickr and at:


  9. @Balakumar Muthu: A-grade browsers are those we test with. Testing has real costs, so keeping the number low is beneficial. Luckily, Netscape shares Firefox’s core Gecko rendering engine, and so while we don’t invest resources to test each page with Netscape, we have a high degree of confidence that the experience will be on par with so-called A-grade browsers.


  10. currently tells newer builds of Safari to “upgrade to a more recent browser”. It would be nice if it didn’t do that.

  11. @Chris: I agree, and we’re making progress.

  12. 简单得创建JAVASCRIPTE WEB丰富界面以及与JAVA服务互相访问…

    简单得创建JAVASCRIPTE WEB丰富界面以及与JAVA服务互相访问…

  13. Yahoo! site also reccomends upgrading to IE 7.0. I hope YUI library don’t become specific to IE 7.0 (intentionally or unintentionally) in near future.

  14. [...] That’s a very pragmatic and efficient framework since it adds scalability for QA. [...]

  15. Browser Support Levels…

    Background Krugle supports a number of different broswer/platform combinations. We prioritize browsers by frequency of use or strategic value. The following url explains how yahoo handles this issue….

  16. Can you provide usage data for each of the browsers on the A Grade browser chart?

    I would be really useful for executives deciding what version of each browser they needed to support.

    I posed this question to a Yahoo Engineer at SES Chicago and he suggested I post it back to your blog. (I forget his name, he was filling in for Tim Mayer). He felt that as the leading property on the Internet, Yahoo! would have a unique perspective on browser utilization and that perhaps you could share it along with the A Grade definitions.

  17. Hello Nate –
    Some of my coworkers and I were wondering what techniques you used to block CSS & JS – are you using client-side techniques such as conditional comments, or are you making the decision on the server side and not sending the CSS/JS to the browser at all?

    Out of curiosity, we browsed some of the Yahoo sites using “C” grade browsers (IE 5.0 PC on for example) from past charts and found that they still tried to render CSS & JS – with mixed results. I don’t make that point to be critical, I just want to clarify if you are indeed attempting to entirely block CSS/JS from C grade browsers.

    Thank you!