Graded Browser Support Update: Q4 2010

By YUI TeamNovember 3rd, 2010

This post announces an update to Graded Browser Support, Yahoo!’s recommended browser testing matrix. The GBS page on the YUI site always has the most current GBS table. This post includes:

Reminder: Graded Browser Support is a QA philosophy, not a report card on the quality of popular browsers. It is designed to provide guidance for QA teams about how best to use their limited testing resources (and to frontend engineers about how to sanely cross-check work across a finite set of browsers). The goal is to be conservative and calculating: We want to test the smallest possible subset of browser/platform combinations, leveraging implicit coverage by testing the most commonly shared core browser engines.

GBS Changes for Q4 2010

Specific changes for Q4 2010 include:

  • Revised support for the fast-iterating Chrome browser; Chrome A-grade testing coverage is now recommended for the latest major, stable version of the browser on Windows XP.
  • Dropped A-Grade coverage for Firefox 3.0.† (moves to X-grade).
  • Dropped A-Grade coverage for Safari 4 on Mac OS 10.5.† (moves to X-grade).
  • Updated Safari coverage to 5.† on Mac OS 10.6.
  • Initiated A-grade coverage for WebKit browsers on iOS and Android OS.
  • Forecast A-grade coverage for Firefox 4.† and Internet Explorer 9 on Windows 7 upon their GA release.
  • Addition of Firefox versions prior to 3.0 to C-grade list.
  • Forecast discontinuation of A-grade coverage for Internet Explorer 6 in Q1 2011; we expect to move IE6 to the C-grade browser list as of the next update.
Win XP Win 7 Mac 10.6.† iOS 3.† iOS 4.† Android 2.2.†
Safari 5.† A-grade
Chrome † (latest stable) A-grade
Firefox 4.† A-grade (upon GA release) A-grade (upon GA release)
Firefox 3.6.† A-grade A-grade A-grade
IE 9.0 A-grade (upon GA release)
IE 8.0 A-grade A-grade
IE 7.0 A-grade
IE 6.0 A-grade
Safari for iOS A-grade A-grade
WebKit for Android OS A-grade


  • The dagger symbol (as in “Firefox 3.6.†”) indicates that the most-current non-beta version at that branch level receives support.
  • Code that may be used on pages with unknown doctypes should be tested in IE7 quirks mode.
  • Code that may appear in IE8’s “compatibility mode,” which emulates but is not identical to IE7, should be tested explicitly in compatibility mode.
  • No guidance is given on iOS or Android OS device usage. The recommendation is that you choose a device most representative of your user base for each OS.

C-Grade Browser List (Draft)

This list represents browsers from which CSS and JavaScript should be withheld. This list remains in draft status.

  • IE < 6 (including Mac OS versions)
  • Safari < 3
  • Firefox < 3
  • Opera < 9.5
  • Netscape < 8

GBS Forecast

We expect to make the following changes in the Q1 2011 GBS update:

  • Discontinue A-grade for Internet Explorer 6, moving it to C-Grade.
  • Discontinue A-grade for Firefox 3.6.† on Windows XP.
  • Move Chrome support from Windows XP to Windows 7.


This update implements the guidance we provided in Q1 2010. Of interest in this update:

  1. Internet Explorer 6: We are forecasting the transition of Internet Explorer 6 from A-grade to C-grade in the next GBS update. The calculus here is simple: The proliferation of devices and browsers on the leading edge (including mobile) requires an increase in testing and attention. That testing and attention should come from shifting resources away from the trailing edge. By moving IE6 to the C-grade, we ensure a consistent baseline experience for those users while freeing up cycles to invest in richer experiences for millions of users coming to the internet today on modern, capable browsers. Note: This forecast should not be taken as an indication that IE6 users will see an abrupt change in their experience of Yahoo! websites in Q1 2011; the change in philosophy toward IE6 will be reflected in new development and products and applied in ways that make sense based on product needs.
  2. Chrome: Chrome has been progressing rapidly through versions, and Google has communicated its intent to continue rapid development and short release cycles. As a result, we’ve modified our GBS strategy for Chrome to advise testing on the latest GA release of Chrome as soon as it is issued, with prior versions moving to X-grade as soon as they are superseded.
  3. Mobile: We’re taking a conservative approach to the addition of mobile browsers to the QA matrix, beginning in this release with the current Android version (2.2) and the two latest releases of Apple’s iOS (which covers the current OS version for iPad and iPhone/iPod Touch devices). We recommend including devices running these operating systems at minimum in your QA battery. Depending on your resources and your focus, you may want to be much more aggressive in supporting variants of Android and other operating systems (like Palm/HP’s WebOS). This GBS recommendation provides a testing surface of 15 browser/platform combinations (once IE 9 and Firefox 4 reach GA), bringing in this first wave of A-Grade mobile browsers while keeping the testing surface at a level consistent with previous quarters.

The GBS Archive


  1. “Discontinue A-grade for Internet Explorer 6, moving it to C-Grade.”


    Just in case you didn’t hear me the first time…


  2. Can we have a world-wide party for this event? I bet even Microsoft will be celebrating this change.

  3. I second the WOOOOOO!!!!!!

  4. One question.

    In the list of C grade browsers, there is Opera 9.5. But there is no Opera 10.* in the general table. I’m confused.

  5. I third the WOOOOOOOOOOOOOO!!!

    I’m surprised to hear about Safari 4, and kind of bummed about Firefox 3, since it was actually decently stable. Oh well…

  6. What a wonderful day, is there going to be party? I know, I know 3 more months to go. But it is nice to know another big player stops considering IE6 to be reasonable browser.

  7. @samba: Opera 10 is an X-grade browser.

  8. Pete Peterson said:
    November 4, 2010 at 11:58 am

    Best news I’ve heard all day.

  9. I don’t think developers should withhold CSS from any browser that has a chance of displaying it correctly. A vast majority of users are going to want a mostly working styled site over a un-styled outline view, which is what happens when styling is withheld.

    Developers should instead make IE 6 an X grade browser (and should do the same for Safari < 3.x). The alternative is to subject IE 6 users to this:

  10. @EJ,

    The better “alternative” is to develop with the C-grade in mind initially via progressive enhancement, which we have promoted since the inception of GBS.

    Calling known incapable browsers “X-grade” goes against the GBS philosophy. By definition, the X-grade experience is “unknown”. We know, however, that C-grade browsers have little chance of dealing with the assets we send, or worse, that these assets will truly break the user experience.

    Keeping in mind that GBS is a testing methodology, while IE6 may “work” as X-grade today, the longer it floats out there untested, the more broken that experience becomes. Shops that adhere to GBS also test the C-grade, ensuring a usable HTML page for any HTML reader without depending on stylesheets or scripts. This allows IE6 and other legacy browsers to be supported indefinitely.

  11. I say let IE 6 users eat an unstyled and unscripted HTML page. Perhaps then they will demand to be allowed to used a modern browser and IE 6 can really die.


  13. Excellent news! Personally I believe that IE6 users should be served a page that looks something like this:

    Supporting IE6 has fed the all-browsers-must-be-supported-down-to-the-pixel-perfect-level antipattern for far too long.

  14. I’m using Windows Vista and Opera.
    Where is my rank ?

  15. Ringman: Any browser that isn’t listed as A grade or C grade explicitly is X grade. Read for more details.

  16. @Eric – any plans to get a nagbar out there to compliment the GBS list? ;-) It’d be good when IE 6 does go C-Grade to be able to message users with what’s happened and provide alternatives.

  17. Hi Eric, curious as to why Firefox 4 isn’t listed under Win XP – is it heading down the ie9 path of requiring hardware acceleration that XP is unable to provide?

  18. Jonathan,

    The thinking is to list FF4 under either Win7 or XP to keep the testing surface as limited as possible; the other platform would be X grade.

    In this case, FF4 debuts in the Win7 era, so it makes most sense to pair it with the current Windows OS version. Your Win7 testing should give you quality implicit coverage for XP, Mac and Linux, so we consider those to be X grade.

    That’s the thinking.


  19. @Sweeney,

    Progressive enhancement is clearly the way to build pages, and I’d argue it’s an important methodology to ensure that older browsers will display something reasonable in the presence of unfamiliar CSS selectors.

    However, I don’t agree that users should ever be subjected to the un-stlyled experience of a site like Yahoo! Sports. Sure the data is there, and readable, but all but the most broken rendering of CSS would be better than this (sorry to repeat):

    This is why I do not think IE should be a C grade browser if it truly means that developers should withhold CSS from it.



    Chrome 10.0 now available for testing.

  21. Sorry but I don’t get it.
    Why isn’t Vista in the list of OS’s?

    oh, and Woooooo!

  22. Barbeque Bob — We haven’t seen a huge number of Vista-specific bugs. Our advice is to invest in the fifteen or so browser/OS combinations listed here and to deal with Vista-specific issues if/when they come up. -Eric

  23. You need to add Chrome for the Mac to the A listing. Just about everyone I know uses Chrome on the Mac. I would also add it for WIn7 – I’m not sure why its only listed for XP?

  24. So… about that IE6 update. Anything new?

  25. Same as Annette – any news on the forecast removal of A-grade support for Internet Explorer 6?

  26. would love a gbs update!

  27. You guys promised an update in quarter 1 which would remove IE6 A-grading. What happened? Can you please post an update.

  28. We missed the Q1 window due to logistics with the 2.9.0 deployment.

    The Q2 update is currently being finalized, and will be coming soon.

  29. Why hasn’t this happened? “We expect to move IE6 to the C-grade browser list as of the next update.”

  30. Because:

    “We missed the Q1 window due to logistics with the 2.9.0 deployment. The Q2 update is currently being finalized, and will be coming soon.”

    Sit tight. So glad it’s still planned though.

  31. Any GBS update? Patiently waiting for IE6 to go away. If so, approximately when do you expect to publish your results?

  32. Another request for GBS update. We are all hoping & waiting for this to happen. Feel free to roll IE7 as a bonus since we had to wait until Q2.