[webkit-dev] Default viewport value on WAP DTDs

Tue May 8 13:07:57 PDT 2012

Hi there,

Now that I have all this info, I will write an email to www-style this
week (hopefully tomorrow). Thanks John Mellor for clarifying what
Android does.

Here is some info about WP7 Internet Explorer which does very similar things:
http://blogs.msdn.com/b/iemobile/archive/2010/11/22/the-ie-mobile-viewport-on-windows-phone-7.aspx

Cheers,
Kenneth

On Tue, May 8, 2012 at 8:58 PM, Ojan Vafai <ojan at chromium.org> wrote:
> On Tue, May 8, 2012 at 11:32 AM, Hugo Parente Lima <hugo.lima at openbossa.org>
> wrote:
>>
>> On Tuesday, May 08, 2012 07:22:17 PM John Mellor wrote:
>> > Both Chrome for Android and the legacy Android Browser do what Hugo
>> > described, i.e. we default to a widthÞvice-width viewport* when an
>>
>> > XHTML-MP doctype is provided.
>> >
>> > And as suggested in wkbug.com/55874, we similarly default to a
>> > widthÞvice-width viewport if a legacy HandheldFriendly meta tag is
>> > present, e.g.:
>> >
>> > <meta name"HandheldFriendly" content"true">
>>
>> >
>> > and if a legacy MobileOptimized meta tag is present then we will use a
>> > viewport with the width provided, e.g. if the following tag is present:
>> >
>> > <meta name"MobileOptimized" content"240">
>> >
>> > we will treat that the same as a "width$0" viewport tag (though IIRC the
>>
>> > legacy Android Browser ignored the provided width and just treated it as
>> > device-width).
>> >
>> > However note that we give these implicit viewport declarations lower
>> > priority than actual viewport meta tags, so irrespective of the order
>> > they
>> > appear in the document, a viewport meta tag will override any behaviour
>> > we
>> > infer from the doctype or those legacy meta tags.
>> >
>> > We do all this because some number of legacy sites depend on this
>> > behaviour. I'm afraid we don't know how common these sites still are;
>> > but
>> > these heuristics have never seemed to cause us any problems.
>> >
>> > It makes sense to propose standardizing the XHTML-MP behaviour on
>> > www-style
>> > since I agree with Kenneth that this is something that should be covered
>> > by
>> > the http://dev.w3.org/csswg/css-device-adapt/ spec. That would also be a
>> > good place to try and standardize how we deal with legacy mobile meta
>> > tags.
>> > And we'd be happy to see any of these heuristics incorporated into
>> > WebKit (either before or after they get standardized) so we don't need
>> > to
>> > fork them.
>>
>> Kenneth pointed that the XHTML-MP behavior is already on the spec, but on
>> a
>> non normative section, the introduction:
>>
>> "Certain DOCTYPEs (for instance XHTML Mobile Profile) are used to
>> recognize
>> mobile documents which are assumed to be designed for handheld devices,
>> hence
>> using the viewport size as the initial containing block size."
>>
>> on http://www.w3.org/TR/css-device-adapt/
>
>
> I see. Given this and the fact that Android already does this, I think this
> change is fine. Do any Apple/iOS folk object?
>
> The Android behavior seems a little more conservative to me, so I'd prefer
> if we did that (e.g. don't mess with zooming). We should make the most
> minimal change we can to optimize compatibility.
>
> Before making this change, I'd still like to see discussion on www-style for
> this. Specifically, it would be good for this to move to a normative section
> and to be more concretely specified. This open-ended language is not useful
> for actually achieving interoperability across mobile browser vendors. It
> should say specifically which doctypes and how it relates to the viewport
> meta tag. Again, I prefer the Android behavior here of always having the
> viewport meta tag win.
>
> Speaking of which, given the note in the spec, has there already been
> discussion on www-style about this?
>
> Ojan
>
>>
>>
>>
>> > Cheers,
>> > John
>> >
>> > *: (unlike Hugo's current patch, we don't add "initial-scale1.0,
>> > user-scalableno", just "widthÞvice-width", since there doesn't seem to
>>
>> > be any reason to assume that XHTML-MP sites want to disable zooming, and
>> > it
>> > may actually lead to a worse user experience).
>>
>> You are right, setting just the width should be enough.
>>
>> > On Sat, May 5, 2012 at 12:58 PM, Kenneth Rohde Christiansen <
>> >
>> > kenneth.christiansen at gmail.com> wrote:
>> > > Hi there,
>> > >
>> > > On Sat, May 5, 2012 at 7:12 AM, Ojan Vafai <ojan at chromium.org> wrote:
>> > > > I see. That's unfortunate. I don't really know the best path forward
>> > >
>> > > here.
>> > >
>> > > > I'm inclined to agree with Alexey that we should at least try to
>> > >
>> > > st
>> ndardize
>> > >
>> > > > this before committing code. It's not clear to me where this should
>> > > > be
>> > > > specced. Easiest path forward is to make this proposal to both
>> > > > whatwg at whatwg.org for the HTML spec and www-style at w3.org for the CSS
>> > >
>> > > Device
>> > >
>> > > > Adaptation spec.
>> > >
>> > > I will pass it by the CSS Device Adaptation spec first as I really
>> > > think it fits there.
>> > >
>> > > > We'll see what the response there is and can decide what to do next
>> > > > based
>> > > > off that response. Does that sound OK?
>> > >
>> > > I think we will add a feature flag for now, together with layout tests
>> > > for a document with XHTML-MP doctype using and not using fixed
>> > > layouting.
>> > >
>> > > > I'm reluctant to make a change like this, but it sounds like there
>> > > > might
>> > >
>> > > not
>> > >
>> > > > be a better choice. One concern I have is how many sites would break
>> > > > due
>> > >
>> > > to
>> > >
>> > > > this behavior? For example, will this fix sites on N9, but break
>> > > > them on
>> > > > Android/iOS or are these wapfor
>> m doctypes never sent to Android/iOS
>> > >
>> > > because
>> > >
>> > > > of UA-sniffing?
>> > >
>> > > It can only break browsers respecting the viewport meta and using
>> > > fixed layouting in some way, those currently mobile browsers. As far
>> > > as I heard Android and iOS are using similar tricks but they seldom
>> > > get the pages due to UA sniffing. I already tried contacting the
>> > > Android team.
>> > >
>> > > Cheers,
>> > > Kenneth
>> > >
>> > > > On Fri, May 4, 2012 at 3:39 PM, Kenneth Rohde Christiansen
>> > > >
>> > > > <kenneth.christiansen at gmail.com> wrote:
>> > > >> Nokia actually looked into this about a year ago and we homogenized
>> > > >> our UA strings across our different devices, so that we could start
>> > > >> to
>> > > >> tell contents providers to give us the best content supported by
>> > > >> our
>> > > >> browsers. Part of this work was actually simplifying our UA string
>> > > >> so
>> > > >> much as possible and it is actually quite similar to what you are
>> > > >> using today.
>> > > >>
>> > > >> The user agent for the N9 browser, for inst
>> nce, is:
>> > > >>
>> > > >> Mozilla/5.0 (MeeGo; NokiaN9) AppleWebKit/534.13 (KHTML, like Gecko)
>> > > >> NokiaBrowser/8.5.0 Mobile Safari/534.13
>> > > >>
>> > > >> The problem is not just the user agent. For instance the user agent
>> > > >> is
>> > > >> known by your Google, and we did pass validation for Tier 1 YouTube
>> > > >> content, but the Google search team, as far as I heard, decided
>> > > >> that
>> > > >> we didn't have enough market penetration for them to turn on Tier 1
>> > > >> content for us, and serves us the XHTML-MP (Tier 3?) content
>> > > >> instead.
>> > > >>
>> > > >> As far as I understand, the decision comes from that team not
>> > > >> wanting
>> > > >> to dedicate resources to make sure the Tier 1 content keeps working
>> > > >> on
>> > > >> our device. I totally understand their reasoning and decision, but
>> > > >> it
>> > > >> is a saddens me given the promise of the open web and HTML5. It is
>> > > >> even more sad that this is not a unique case and it will only be
>> > > >> solved the day content providers stop looking at the user agent
>> > > >> strings.
>> > >
>> >>
>> > > >> Kenneth
>> > > >>
>> > > >> On Fri, May 4, 2012 at 11:32 PM, Ojan Vafai <ojan at chromium.org>
>> > > >> wrote:
>> > > >> > Instead of UA faking, is it possible for you to pick an actual UA
>> > >
>> > > string
>> > >
>> > > >> > that is more compatible with the web at large? For Chromium we
>> > > >> > experimented
>> > > >> > with making the most minimal UA string possible without a big
>> > > >> > loss in
>> > > >> > web
>> > > >> > compatibility. To our disappointment, we found we had to match
>> > > >> > the
>> > > >> > Safari UA
>> > > >> > string almost exactly. Our current UA string is "Mozilla/5.0
>> > > >> > (X11;
>> > >
>> > > Linux
>> > >
>> > > >> > x86_64) AppleWebKit/536.6 (KHTML, like Gecko) Chrome/20.0.1096.1
>> > > >> > Safari/536.6". The parts that we found to be safe to change are
>> > > >> > the
>> > > >> > platform
>> > > >> > names in the first sent of parenthesis. The version number after
>> > > >> > AppleWebKit. And the Chrome/versionNumber section. Even getting
>> > > >> > rid
>> > > >> > of
>> > > >> > the
>> > > >> > Safari/versionNumber caused us significant web compatibility
>> > >
>> >> > problems.
>> > > >> >
>> > > >> > That said, we did all this testing in 2008. The web may have
>> > > >> > changed
>> > > >> > considerably since then. In either case, if your UA string
>> > > >> > diverges
>> > >
>> > > too
>> > >
>> > > >> > much, I expect this problem will just be the tip of the iceberg
>> > > >> > of
>> > > >> > compatibility problems you'll encounter. So it might be worth
>> > > >> > considering
>> > > >> > changing your UA string before trying to add new DocType
>> > > >> > switching
>> > > >> > behavior.
>> > > >> >
>> > > >> > Ojan
>> > > >> >
>> > > >> > On Fri, May 4, 2012 at 10:53 AM, Hugo Parente Lima
>> > > >> > <hugo.lima at openbossa.org>
>> > > >> >
>> > > >> > wrote:
>> > > >> >> On Friday, May 04, 2012 10:11:07 AM Ryosuke Niwa wrote:
>> > > >> >> > On Fri, May 4, 2012 at 9:39 AM, Kenneth Rohde Christiansen <
>> > > >> >> >
>> > > >> >> > kenneth.christiansen at gmail.com> wrote:
>> > > >> >> > > This is not supporting XHTML-MP, as we are not implementing
>> > > >> >> > > anything
>> > > >> >> > > special to support it. We are basically showing the content
>> > > >> >> > > as
>> > >
>> >> >> > > it
>> > > >> >> > > was
>> > > >> >> > > HTML5 and that solves most real use-cases. Injecting a
>> > > >> >> > > proper
>> > > >> >> > > viewport
>> > > >> >> > > configuration makes it also layout properly.
>> > > >> >> >
>> > > >> >> > Okay. Is this change observable by the page? Or more
>> > > >> >> > specifically,
>> > > >> >> > can a
>> > > >> >> > web page currently feature-detect whether a given browser
>> > > >> >> > support
>> > > >> >> > XHTML-MP
>> > > >> >> > by checking the size of the viewport?
>> > > >> >>
>> > > >> >> The page knows nothing, just as it knows nothing about the ~980
>> > >
>> > > pixels
>> > >
>> > > >> >> used
>> > > >> >> for the canvas width, it's a matter of change a magic value to
>> > > >> >> the
>> > > >> >> device-
>> > > >> >> width to get websites better looking.
>> > > >> >>
>> > > >> >> I attached screenshots of MiniBrowser runnin with and without
>> > > >> >> the
>> > >
>> > > patch
>> > >
>> > > >> >> using:
>> > > >> >>
>> > > >> >> MiniBrowser --window-size 480x720 http://m.yahoo.com
>> > > >> >>
>> > > >> >> Without patch (viewport of 980 pixels):
>> > > >> >> https://bug
>> 85425-attachments.webkit.org/attachment.cgi?id 0272
>>
>> > > >> >> Patched (viewport of 880 pixels)
>> > > >> >> https://bug-85425-attachments.webkit.org/attachment.cgi?id 0273
>>
>> > > >> >>
>> > > >> >> > If the answer is yes, then we'll be breaking the feature
>> > > >> >> > detection.
>> > > >> >> >
>> > > >> >> > Unfortunately most unknown mobile browsers tend to get lots of
>> > > >> >> >
>> > > >> >> > > XHTML-MP. Heck, we even get that for google.com on the Nokia
>> > > >> >> > > N9
>> > > :
>> > > :-(
>> > > :
>> > > >> >> > > as
>> > > >> >> > > well as other high profile sites.
>> > > >> >> >
>> > > >> >> > Yeah, it's very unfortunate.
>> > > >> >> >
>> > > >> >> > This makes the sites render acceptable, until we can advocate
>> > > >> >> > the
>> > > >> >> >
>> > > >> >> > > sites to accept our user agent, something which we haven't
>> > > >> >> > > always
>> > > >> >> > > had
>> > > >> >> > > luck with. Google for one didn't want to provide us the Tier
>> > > >> >> > > 1
>> > >
>> > > site
>> > >
>> > > >> >> > > of
>> > > >> >> > > google.com on the N9, even though it works a lot better t
>> an the
>> > > >> >> > > XHTML-MP version we are being served. I don't see this
>> > > >> >> > > situation
>> > > >> >> > > change any time soon.
>> > > >> >> >
>> > > >> >> > Can we work-around this issue by faking the user agent string?
>> > > >> >>
>> > > >> >> If you are working on your own browser you wont be telling every
>> > > >> >> website
>> > > >> >> that
>> > > >> >> you are a iPhone forever, at least you will not be happy doing
>> > > >> >> that.
>> > > >> >>
>> > > >> >> Regards.
>> > > >> >> Hugo Parente Lima
>> > > >> >>
>> > > >> >> _______________________________________________
>> > > >> >> webkit-dev mailing list
>> > > >> >> webkit-dev at lists.webkit.org
>> > > >> >> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
>> > > >> >
>> > > >> > _______________________________________________
>> > > >> > webkit-dev mailing list
>> > > >> > webkit-dev at lists.webkit.org
>> > > >> > http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
>> > > >>
>> > > >> --
>> > > >> Kenneth Rohde Christiansen
>> > > >> Senior Engineer
>> > > >> Nokia Mobile Phones, Browser / WebKit
>> eam
>> > > >> Phone  +45 4093 0598 / E-mail kenneth at webkit.org
>> > > >>
>> > > >> http://codeposts.blogspot.com ﹆﹆﹆
>> > >
>> > > --
>> > > Kenneth Rohde Christiansen
>> > > Senior Engineer
>> > > Nokia Mobile Phones, Browser / WebKit team
>> > > Phone  +45 4093 0598 / E-mail kenneth at webkit.org
>> > >
>> > > http://codeposts.blogspot.com ﹆﹆﹆
>> > > _______________________________________________
>> > > webkit-dev mailing list
>> > > webkit-dev at lists.webkit.org
>> > > http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
>>
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>
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-- 
Kenneth Rohde Christiansen
Senior Engineer
Nokia Mobile Phones, Browser / WebKit team
Phone  +45 4093 0598 / E-mail kenneth at webkit.org

http://codeposts.blogspot.com ﹆﹆﹆