IE8 and CSS 2.1 Testing

Since I joined the IE team at the beginning of 2007, it has become clear to me how important it is for web developers to predict how a given browser will work.  I’ve certainly heard and read how very important it is to web developers to minimize the cost of supporting each additional browser version.  In apparent contradiction to this, everyone needs continued innovation in the browser to create new online business opportunities. 

One of the most important ways to ease development costs is to support a well-defined set of web standards in all the browsers.  This frees up developers’ time to spend on their site innovation rather than porting and testing work.  However, sometimes there are ambiguities or optional items in the specifications, such as the behavior of tables.  This naturally results in browsers that behave differently.

The Internet Explorer team is serious about enabling web developers to be the most effective and efficient as possible.  One very important way we can do this is to support and contribute to the web standards.  For the Internet Explorer team, we will do this in multiple ways including implementing support for standards and driving to cut the ambiguity in these industry standards’ specifications.

I believe the way to cut through the ambiguity is to have a set of tests that can help define how the implementation should actually work.  The W3C’s CSS Working Group has a set of 487 tests today in the CSS Working Group’s level 2 revision 1 test suite.  We just submitted over 700 tests to the W3C for possible inclusion into the official test suite.  We’re providing these using the BSD License.  We wrote these to test the CSS 2.1 behavior in IE8 beta 1.  The coverage they provide is for both basic property support and the scenarios called out in the CSS 2.1 spec.  We strongly believe in the W3C and how its test suites can ultimately help the web developers of the world spend more time creating new web experiences and less time dealing with browser differences.  The feedback regarding the first set of submitted CSS 2.1 tests will help us improve these tests and strongly guide our future test submissions to the CSS Working Group and others. 

The IE Test Team welcomes your feedback about our CSS 2.1 tests including our interpretation of how they test the CSS 2.1 support in IE8 Beta 1.  If you’re interested in commenting on the tests, I encourage you go to join the existing W3C’s 2.1 Test Suite Mailing List discussion on the topic.  I truly believe that starting with IE8 Beta 1 we’ve begun a journey toward making it easier for you to build the web in a standards-based, predictable way. 

Thanks a lot,

Jason Upton
Test Manager
Internet Explorer

Comments (50)
  1. Steve says:

    Not sure about how this might relate to a given test but…

    If I have a block element with display:none; set as part of a CSS class, and I later via JS remove that class (thus showing the content), links that were added to content within that block will not work (in my case said links call JS via onclick)

    I’d provide a test case, and submit a bug to connect, but alas, we’re locked out.

  2. Steve says:

    I should have noted… this is a regression bug.  Same content served up to IE6, IE7, IE8, Firefox, Safari, & Opera… all work *except* IE8 Beta 1.

  3. Ron says:

    Argh, why do you (MS, not the author) have to post _everything_ in less than one working week? It’s like a drought for 95% of the year and then suddenly there’s a flood of content, which could have been released prior to IE8’s launch.

    Internet Explorer isn’t some state of the art, revolutionary, secret product. It’s just another web browser. Don’t starve us of information, and then try to force it down our throats.

  4. Ron says:

    How do you skip to a certain test in the suite, while keeping the navigation?

  5. Stifu says:

    lol, it’s true there is like an article flood all of a sudden…

    There is also a lot of repetition between articles (3rd time those 700 tests are mentioned), resulting in confusion and little actual information.

    Still, that easily beats silence, better too much than not enough.

    I’ll check out those tests and see if I find any problem with Firefox 3… I haven’t installed IE8 yet, I think I’ll wait for a later beta, as the fact it’s tied to the OS and overwrites the previous version is a bother.

    On a side note, I could never install IE7 on my computer for some reason, the installation keeps failing. I do have the needed OS (XP SP2) and have followed the FAQ about installation problems, to no avail.

  6. FarStrider says:

    when is object canvas support going to be improved

  7. Jron says:

    "We strongly believe in the W3C and how its test suites can ultimately help the web developers of the world spend more time creating new web experiences and less time dealing with browser differences."

    Does anybody else see the hypocrisy in this?

  8. David Naylor says:

    "Since I joined the IE team at the beginning of 2007, it has become clear to me how important it is for web developers to predict how a given browser will work.  I’ve certainly heard and read how very important it is to web developers to minimize the cost of supporting each additional browser version.  In apparent contradiction to this, everyone needs continued innovation in the browser to create new online business opportunities."

    No, you see this is what sets MS thinking apart from the other browser developers thinking. Developing web standards doesn’t have to go against predictability. It only requires you to advance the standards in a way which the IE team seems very uncomfortable with. I.e. sitting down with the other browser makers and discussing thigs, thinking things out, setting a spec and then implementing. Hardly impossible.

  9. David Naylor says:

    Sorry, but I have to post a second comment:

    "The Internet Explorer team is serious about enabling web developers to be the most effective and efficient as possible."

    We’ve been hearing this all week, and frankly it’s getting a bit sickening. Like a man who has been starving in the desert and then suddenly is being fed heaps of cream cake.

    Less of the fancy words and more details on what you’re doing please.

    You know what I’d really like to see here? One of those short, simple personal posts that just says something along the lines of "Yay, we fixed CC3 selector X", or whatever, instead of these long, super edited management-approved posts.

    The CSS tests are great though, but since most other browsers have already implemented CSS 2.1 they are probably of limited value(?).

  10. Seb says:

    F**king hell guys, you all slag MS off for doing everything wrong, and when they do something "right" you all slag them off for "ramming it down your throats".  What’s wrong with a little praise on a job well done?  Morons.

  11. Neal says:

    Why are so many web pages broken (rendered wrong) in IE8 that worked perfectly in IE6, IE7 and other browsers? I am new to the whole beta experience but I was under the assumption that beta means the developer is pretty confident when their software.

  12. Andrew Durdin says:

    The CSS 2.1 test at

    appears to be incorrect. The second line states "This text should NOT be green.",

    as its tag does not have a "lang" attribute to be matched by the :lang selector.

    However, section 5.11.4 of the CSS 2.1 specification states "The pseudo-class

    ‘:lang(C)’ matches if the element is in language C", and makes clear that this

    should match if the inherited language of the element is language C (NOT whether it has a "lang" attribute).

    The HTML 4 specification, section 8.1.2, states:

       An element inherits language code information according to the following order

       of precedence (highest to lowest):

       1. The lang attribute set for the element itself.

       2. The closest parent element that has the lang attribute set.

       3. The HTTP "Content-Language" header.

       4. User agent default values and user preferences.

    Since none of 1, 2, or 3 above are met in this test, then the language of the p element depends on the user agent, so should be green or not green accordingly.

  13. David,

    We *are* sitting down with other browser makers. We’re active in many of the W3C working groups (including chairing the HTML working group). And, we’ve worked together on non-stds things like EV certs. On top of that, we’ve worked with advocacy groups like the Web Standards Project to make sure we lots of points of view. This contribution of the test cases is just another example of how we’re trying to work better with others.

    I think if you run the tests in the different browsers, you’ll see why they’re needed. While all browsers pass most of them, there are a bunch where only some of the browsers pass. There’s already an interesting discussion going on about what the right interpretation of the stds is. That’s what makes the tests useful; it’s easy to say you support stds, but until there are tests, there’s no way to prove it. None of the browsers currently has a full implementation of CSS 2.1, and as we’re already seeing, there are differences between how we’re interpreting the spec.

  14. Andrew Durdin says:

    Also, the test at is invalid; CSS 2.1 does not specify a color name "WindowsText".

  15. Andrew Durdin says:

    Anyway, it’s great to see that you guys are rigorously testing the CSS support in IE8, and even better that you’re contributing tests that all browser makers can use.  Despite what the various "morons" (as Seb above said) say, this indeed can only help encourage the full and correct implementation of web standards in all browsers.

  16. Ron says:


    My issue is that this is the information they’ve been holding off all this time, I doubt they only just decided what their IE8 plans are within the last week.

    I’m not whining about having too much information, but about the fact that this information could have come earlier.

    Did you know that they tried to keep the name of IE8 a secret? That was until Bill G leaked the name.

    "BILL GATES: I’ll have to ask Dean what the hell is going on. I mean, we’re not — there’s not like some deep secret about what we’re doing with IE."

  17. Mike M says:

    Andrew Durdin is correct when talks about the :lang pseudo-class but I do have an observation.  Under both Firefox 2 and Opera 9.5 the same behavior occurs where the text in the second paragraph is also not in green.  But, when I add ‘dir="ltr" lang="en" xml:lang="en"’ to the HTML tag itself (which should have this sort of information in it to begin with BTW) the text then becomes green because the paragraph is properly inheriting the language.  Now the reason for this behavior could be because neither Firefox nor Opera are properly implementing the spec but the behavior of IE is consistent with others.  Surprisingly though Safari 3 implements it correctly.

  18. Bill says:

    @Ron: Microsoft’s plans are always being reevaluated based on changing market conditions, legal factors, technology initiatives, etc.  

    After the Vista mistakes, they’ve dramatically cut back on the number of announcements, holding them until confidence is high.  The fact that they changed their mind about the default render mode (announced just weeks before) suggests that this was, in fact, a late-breaking change.

  19. JurgenDoe says:

    When does Microsoft stop working on a crappy browser like IE and uses better FF?

    IE never reads CSS correct and doesn’t support hover at all. If you guys don’t know what ppl like  and or would make them happier please visit my site and look at my journal. Use FF and use your own crap IE and you’ll see what I’m talking about. In the meanwhile I suggest you better use FF as your browser because this browser works very well.



  20. ricktendo64 says:

    Yep, I see exactly what you mean JurgenDoe. I clickd your name and it took me to your website and you are right, CSS is not displayed properly in IE7 or 8 (but in FF it looks fine)

  21. JurgenDoe says:

    You see that is what I’m talking about and that’s why I suggest they better stop building a crappy browser like IE and use better FF 🙂

  22. P says:

    This page contains some testcases that IE8 is failing. dunno if the same tests are allready includedn in the 700+ testcases, but would be interesting, I think.


  23. David Naylor says:

    Well, according to Anne v Kesteren’s post here

    you for instance are not cooperating on the XDomainRequest. But then I don’t know a thing about that stuff so I’m only taking his word for it.

  24. Goujon says:

    Hey! I have simple login form on my site (with post-submit validation) and when I click on any link within the site (or entering address directly) each time a warning window appear with "Do you want to navigate away from this page blah blah blah. You made some changes to the form blah blah blah." – but problem is that I never touched any of form fields and there’s nothing wrong with the code (in at least 5 browsers incl. IE 6/7). That’s very annoying. Is there some new IE8 setting that cause this issue? (it’s bad if it’ll be set as default) What can I do? Thanks in advance.

  25. Just out of curiosity: Do you test all these cases also with zoom and/or text size applied to different levels? I remember a few pages (including some of mine) where the layout breaks if you zoom the page (which shouldn’t happen) or change the text size (which can happen with stupidly coded pages). Anyway, especially zooming is a problem sometimes.

  26. anony.muos says:

    Can the IE team document the "Integrated Windows Authentication" protocol so more browsers support it?

  27. Brian LePore says:

    If we can’t get weekly builds on IE, is it at least possible to get weekly updates on the Developer toolbar? This is a great idea, but from my testing in the last day seems monumentally buggy. It says that CSS attributes are being inherited from elements that it shouldn’t be, and there is no way to add additional elements unless your element already has a style element to which you can modify the value of, and even then it doesn’t always work 100%. Rarely does unchecking some of the buttons actually do anything. Should it? If not, why is it there.

    I’ve been trying my darndest to figure out why there appears to be additional top/bottom margins applied to windows created using the Prototype Window Class (see the second example on the samples page), and why the entire layout  VANISHES whenever you try to move said Window. It comes back when you release the mouse, but it was VERY scary the first time I did it.

    That and the unnecessary horizontal scrollbar are the only issues that I’ve seen. Shouldn’t overflow-x: atuo; (or hidden) on the html element fix that?

  28. Bill says:

    There is problems with the chapter 10 tests; the ruler is the wrong size if your screen dpi is not 96. On my monitor (120dpi) the ruler is a different size in Firefox than it is in IE (though the green is the same size in all cases except when specified at 96 pixels, then the IE one is 120px and the Firefox one is 96px).

    It is almost as if IE pretends the viewport is 96dpi no matter what it actually is, then when rendering scales it to the actual screen resolution. Is there any explanation for this?

    This does seem to explain the size difference I see when comparing acid test sizes between the two browsers and why the IE one is larger than the reference drawing by 25%.

  29. phil_r_5150 says:

    Sounds to me like MS have decided themselves what the CSS standard is, then have written tests to back that up.  If W3C already have 480 tests, why do MS need to add 700 more?  If FireFox/Safari/Opera fail on those tests, does that mean those browsers aren’t compliant?

  30. Joshbw says:

    "Well, according to Anne v Kesteren’s post here"

    It does deviate, but the proposed standard is wrong.  allowing cross domain requests for protected data is a bad idea from a security standpoint, a horribly bad idea.  The rationale that the W3C puts forth is that it is no different than img or form, ignoring the fact that in the latter instances it is the browser making the requests and in the former it is any freaking script on the internet.

    Standards support is great, but when a standard fails to properly consider the security implications of an issue I will not fault a company for erring on the side of protecting their customers rather than blindly supporting a standard.  The fact that other browser vendors haven’t chimed to state how security oblivious the proposed standard happens to be is quite worrisome; I wouldn’t necessarily expect Apple or opera to speak up, but I expected more from Mozilla now that Window Snyder is chief security something or other.

  31. @phil_r_5150: CSS 2.1 is a huge spec. The 1.5k tests that currently exist are no where near enough in my opinion, and yes, Firefox, Safari, and Opera do at times have bugs.

  32. EricLaw [MSFT] says:

    @Someone: Integrated Windows Authentication is the combination of Kerberos and NTLM.

    Kerberos is a standard, while NTLM is already supported by both Firefox and Opera.

  33. wilkinism says:

    Facilitating broad standards adoption in the industry is wonderful and long overdue, but please lead by example: I found 860 HTML errors on your blog’s homepage.

  34. Hello all,

    HTMLCollection of rows, HTMLCollection of cells are not supported anymore. Possibly this is because

    "there are ambiguities or optional items in the specifications, such as the behavior of tables." – Jason Upton

    , which, I suppose, would need to be clarified first before implementing them back.



    1- load

    2- in Developers Tools, Script tab, Immediate window:


    returns "TABLE"

    document.getElementById("idTable").rows returns

    "Unexpected call to method or property access."

    Also, filters collection is not supported… most likely (very reasonable assumption) that this is still a beta.

    In ,


    returns {…}

    Best regards, Gérard

  35. @Jason Upton and Tony Chor


    "Conflict between Mime Type and Document Type

    The document is being served with the text/html Mime Type which is not a registered media type for the XHTML 1.1 Document Type. The recommended media type for this document is: application/xhtml+xml"

    Why create an XHTML 1.1 document to begin with? served as text/html?

    No to XHTML (at least served as text/html):

    Beware of XHTML (with 16 quotes from browser vendor representatives)

    There is no lang attribute in XHTML 1.1 !

    If Microsoft had created an HTML validator as an add-on extension or built-in developer tool, just like Marc Gueury

    has for Firefox, then we/anyone/everyone would have immediately seen there were validation errors with that



    "(…) Webpage Quality indicator icon (smiley or green check for valid page, frown or red ‘X’ when invalid) on the statusbar (or somewhere else) which when clicked would report more info to the user and give him more options among which one would be to validate the page with the W3C validator.":

    I have detailed such proposal/suggestion in 3 distinct* webpages in 2005, 2006, 2007 and elsewhere.

    Regards, Gérard

  36. Tino Zijdel says:

    About table-rendering: unfortunately IE’s current rendering algorithm makes it impossible to use text-overflow within non-fixed layout tables which is a real pain. There is effectively no way to restrict the width of a table while still allowing for dynamic column sizing which can easily break layouts that contain complex tables with lots of dynamic data.

  37. Webdesign says:

    "We strongly believe in the W3C and how its test suites can ultimately help the web developers of the world spend more time creating new web experiences and less time dealing with browser differences."

    Does anybody else see the hypocrisy in this?

  38. JurgenDoe says:

    @ Freudi

    maybe you’ve seen the errors in IE but not in FF and I would suggest you visit my site with both browsers and see what happens after you hover over the names…

    Nothing happens with IE but with Ff …omg I see something

    Microsoft really should learn to write better scripts and support better hover and CSS like Firefox is doing. IE is crap and it wont change and I suggest everybody to change to a great browser where you can see and read everything fine without crashing on you ROFL

  39. JurgenDoe says:

    Here are some images I made in a view with FF and IE..You can see on the arrows where IE doesn’t show the CSS correct and even support hover at all

    1. FF – preview

    2. IE – preview

  40. ricktendo64 says:

    WOW Jurgen thats bad!!!… WTF is wrong with IE8 guys?

    Hope you fix it

  41. thacker says:

    Have run across the following that has me somewhat concerned:

    The meta equivalent IE7 has been used on a content page.

    From my understanding this forces the IE7 engine within IE8 Beta.

    IE8 is used without using the "Emulate IE7" function.

    Conditional comments that support IE7 will only work with "if lte IE8". Will not function with "if lt IE8" or with any reference to IE7.


  42. @JuergenDoe

    Once again: Your site isn’t is Valid XHTML 1.0 Transitional nor is your CSS.

    Before complaining about IE8b1 not rendering as it should (which for sure is true at least at this state of the beta cycle), it "may" be a good idea to rule out the errors present on your site(‘s code).



  43. Jason Upton [MSFT] says:


    Thanks for the great comments so far.  They’re great!  Please keep the constructive comments coming.  

    Tests are software too, so despite running these a lot and having multiple people review them, there could be minor bugs.

    Here are a couple general points:

    1.  I encourage you to run these on any browser that claims CSS 2.1 support, especially IE8 Beta 1.

    2.  When in doubt, read the CSS 2.1 spec and let us know if you think we read it wrong.

    3.  If you have testcase-specific comments, I strongly encourage you to post them to the W3C’s 2.1 Mailing list at

    4.  We’ll be primarily mining that list for possible changes to the tests based on the feedback.



  44. Jason Upton [MSFT] says:


    That looks like a bug – thanks.  lte IE8 should work in both cases since the version vector is IE7 with the button down and IE8 with the button up.

    However, if a user is running "button up" they’ll use the IE8 conditional comments regardless of the META tag on the page.


  45. JurgenDoe: You noticed that deviantART isn’t parsed in IE 8 mode by default (check the developer tools). Thus complaining about CSS issues on that page is futile unless you switch the rendering mode. As a matter of fact, the hover you complained so loud about _does_ work as intended by you or whoever else. The only thing I see that goes wrong there is that the Journal renders below the end of the left column. But that’s not the issue you complained about. So please do us all a favor and do some research before jumping into everyone’s face.

  46. thacker says:


    Version vector should also target any version less than and not equal to IE8, [if lt IE8], with the use of meta tag specification to IE7. I view that ability important to exclude the IE8 beta engine for existing Web content.

    One important thing developers should be aware is that use of the meta tag does not change the user agent string.  The user agent string still remains IE8. This requires a change to any referenced conditional comments/vector versions used within the content when the meta tag is used to specify IE7.

    Whether or not internal changes can be made to IE8 that use of the meta tag will also modify the user agent string, should be considered. I don’t know if that is even practical or can be done from your development standpoint.


  47. Paulo Cezar says:

    Min-height has problems again. Block treatment fail, like firefox.

  48. Erika Doyle [MSFT] says:

    @Tino Zijdel

    Hi Tino,

    Could you give us an example of the scenario you describe, where auto-sizing the columns of a fixed layout table does not achieve the results you are looking for?

    Thanks—we really appreciate your feedback.


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