Graded Browser Support Update: Q1 2010

By YUI TeamFebruary 16th, 2010

This post announces an update to Graded Browser Support. The GBS page on the YUI site always has the most current GBS table. This post includes:

GBS Changes for Q1 2010

Specific changes for Q1 2010 include:

  • Initiated A-Grade support for Chrome 4.0.† on Windows XP
  • Replaced Windows Vista with Windows 7 in the testing matrix (dropping IE7 from that platform while retaining it on XP)
  • Moved Opera 10.† to X-Grade from A-Grade
  • Replaced Firefox 3.5.† with Firefox 3.6.† in the testing matrix
Win XP Win 7 Mac 10.5.† Mac 10.6.†
Firefox 3.0.† A-grade
Firefox 3.6.† A-grade A-grade A-grade
Chrome 4.0.† A-grade
IE 8.0 A-grade A-grade
IE 7.0 A-grade
IE 6.0 A-grade
Safari 4.0.† A-grade 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.

GBS Forecast

We expect to make the following changes in the Q2 2010 GBS update:

  • Discontinue A-grade for Firefox 3.0.†, moving it to X-grade.


This update implements the guidance we provided in Q4 2009. That update generated significant discussion, and high-quality input from Opera is included in the comments thread; I encourage you to refer to that update for more details. Of interest in this update:

  1. Chrome: Chrome’s continued growth argues compellingly for its inclusion in the A-Grade. Discussion among members of the GBS committee focused around when, not if, Chrome would be promoted into the testing matrix, and there was a strong consensus that it belongs there today.
  2. Opera: Refer to the Q4 2009 GBS update for a discussion of the decision to move Opera to X-Grade. Worth noting here is that YUI specifically and Yahoo more broadly continue to support Opera — just as we continue to support X-Grade browsers in general. The GBS provides guidance for formulating QA testing matrices, and our recommendation as of Q1 2010 is that Opera be grouped in the X-Grade along with other high-quality, low-marketshare browsers. Opera is an excellent browser — we expect Opera users to have a good experience on Yahoo! sites and YUI-based sites, and we’ll continue to investigate bugs related to Opera as they are identified.
  3. Windows Vista and Windows 7: By volume, client-side defects that are specific to a single version of Windows (as opposed to a version of Internet Explorer) are relatively low. Our experience has been that Vista-specific testing has not led to a significantly differentiated set of bugs compared with testing on XP. With that in mind, we’ve decided to replace Vista in the testing matrix with the newer and ascendant Windows 7 platform, keeping the testing surface to 4 unique platforms while bracketing the Windows continuum with the evergreen XP and the newer Windows 7. While Vista remains a popular operating system, and QA engineers and developers should retain access to Vista environments to investigate bugs when reported, we advise QA departments to begin migrating their automated testing platforms to Windows 7 at this point.

Our quarterly reminder: Graded Browser Support is a QA philosophy, not a report card on the quality of popular browsers. It’s 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.

The GBS Archive


  1. Thanks for the update!

    Good to see Chrome up there, but I’m curious why it’s just on Windows XP for now. Is it because of market share, or because there’s not much noticeable difference between Chrome on Windows XP and Chrome on Windows 7?

    Or I suppose it might just be a conservative approach of slowly adopting the browser into GBS?

  2. David,

    The goal is to get the best bang for your buck. Our assumption is that Chrome on XP and Chrome on Win 7 are going to be very similar, and that the former will net you coverage for a larger audience and a particular target audience of people who are leaving behind IE 6 for a more secure, more modern browser. I don’t think there would be a wrong decision here — the advice is to move Chrome into your testing matrix because of its rapid uptake.

    A more interesting question (to my mind) will revolve around Chrome on the Mac — it will be interesting to see where the marketshare numbers go for that version of the browser.


  3. Too bad IE6 is still on this list.

  4. IE6 is still there for some time, I guess as long ITs departments have not upgraded XP to Seven

  5. Did Windows 7 ever come with IE7? :-/

  6. I too am confused why Windows 7 with IE7 is listed. It seems impossible to get that configuration without some jiggery pokery with VMs. Please can anyone clarify why it’s included and the easiest way for me to get IE7 on a Windows 7 laptop.


  7. @Frage and @RoryH:

    Agreed — IE7 shouldn’t have come across in dropping Vista for Windows 7; we’ve amended the chart to reflect this.


  8. can IE6 not be downgraded based on a percentage of worldwide use? Listing IE6 as an A-grade experience is just simply untrue regardless of the corp world’s resistance to upgrade based on cost.
    I thought this list was reflecting Standards, rather than percentage of world resistant to change.

  9. When will there be an update to cover Chrome 5 and Safari 5?

  10. cyclist —

    The next update is expected around the beginning of Q3. Chrome 5 and Safari 5 will be A-Grade as of that update — but it makes sense to be testing with them today.


  11. I am having issues with viewing my website through different browsers. I am running XP and have IE8, Firefox 3.6, and Chrome 4.0. All are A-list for XP, but my site looks ridiculous viewed through Chrome. Any ideas?

  12. You should be testing Chrome 6.0 instead. By the time Q3 rolls by, Chrome 6.0 would have replaced Chrome 5.0, knowing how Google does their thing.

    Also you should start testing Firefox 4.0 and replace Firefox 3.6 with Firefox 4.0 on the chart.

  13. Any idea when the next update will be coming (considering it’s already the middle of August and the last update seems to be this Q1 one from half a year ago in February)?

  14. What about mobile browsers? I stumbled across a minor bug today that affects the stock Android browser in HTC phones but that doesn’t affect the iOS browser.

    Should one not bother filing tickets/test cases for that kind of thing?

  15. @Test — yes, another update is coming soon.

    @JoshL — It’s worth filing a bug. Android’s webkit is an X-grade browser under our current policy — and we’d want to know about X-grade bugs, even if not all of them will warrant a fix.


  16. YUI Folks, it would be great to start tracking these X-grade browsers more closely. Android specifically has some issues that are hard to nail down and test for consistently. Due to flood of devices on market from APAC, there are a lot of Android 1.6 devices on the market, odd sized screens that aren’t phones, and we’ll see a huge wave in Dec of tablet oriented and MID type devices coming in December based on 2.2, which probably exhibit many of the same browser quirks.

  17. Hello,

    When do you think Safari 5 will be added to the AGB list? Also, are there similar GBS initiatives at Yahoo for mobile devices?

    Thank you.

  18. Safari 5 will be an A-grade browser as of the next GBS update.

  19. @truedat: Dealing with the proliferation of Android OSes and their browsers is one of the defining challenges of the next few years. You absolutely want to be treating Android 2.2 as an A-Grade browser today (and iOS 4). -Eric

  20. Any approximate ETA (or at least a general time period) as to when the next update might be coming? Seems like Chrome 6 would already be on that instead of Chrome 5 that never even got a chance to even make it on it.

  21. @Test — Two things — Yes, we’ve been slow getting the current update out; my apologies for that. And the rapid iteration of Chrome doesn’t fit well with a quarterly update system. We need to give better clarity about how the recommended testing surface should be modified when new Chrome versions are released. We’ll do that in the coming update, which is probably two weeks out. -Eric

  22. The C-Grade list suggests we should think about hiding CSS and JavaScript from older versions of FF, Opera and Safari. Does anybody have suggestions on how to do that?

  23. Tyler Rasmussen said:
    October 7, 2010 at 11:28 am

    What I don’t understand (though I do, don’t get me wrong, just hate it like everyone else)…why is IE 6.0 an A-grade browser? Specifically, the definition of A-grade browser includes modern (with the word “and” which has clear meanings in a coder’s mind), of which IE 6 (and arguably 7 and 8) is most definitely not. IE6 should be downgraded to a new category of “B-Grade” : crappy browsers that are unfortunately very popular and constitute a statistically significant number of internet users. I would love to make it C-Grade, but the definition of C-Grade, due to IE6 popularity, does not fit either.

    @Eric Miraglia – “2 weeks out” becomes 3.5 weeks. Will we ever see an update?

  24. @Tyler — Fair criticism — I apologize for the delay.

  25. A quibble about the C-grade list…
    The ‘less than’ symbol (<) was used to indicate versions previous to those on the A-grade list, as in "Safari < 3". Given that Safari 4 is the A-grade, the 'less than or equal to' symbol (≤) would seem to me more appropriate, as this would logically include Safari 3.

  26. I think the C-grade list is correct; it’s saying to withhold CSS/JavaScript from Safari 1 and 2, but not from 3. Version 3 is no longer A-grade but you shouldn’t withhold the CSS and JavaScript from Safari 3 users as it is likely to still render as expected.


    Chrome 9.0 trunk builds now available for testing.

  28. Any news on when we will see an update?

  29. [...] update implements the guidance we provided in Q1 2010. Of interest in this [...]