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Re: CSS Device Adaptation and legacy meta tags and doctypes

From: Kenneth Rohde Christiansen <kenneth.christiansen@gmail.com>
Date: Fri, 25 May 2012 01:00:46 +0200
Message-ID: <CAEC208tj8XwmHdkMe2EPXqxw=jgvFOu4PWAfd+PZruTka87iOg@mail.gmail.com>
To: John Mellor <johnme@chromium.org>
Cc: www-style list <www-style@w3.org>, Peter Beverloo <peter@chromium.org>, Hugo Parente Lima <hugo.lima@openbossa.org>, Ojan Vafai <ojan@chromium.org>, Rune Lillesveen <rune@opera.com>, Øyvind Stenhaug <oyvinds@opera.com>, florianr@opera.com
Hi there,

TabAtkins told me that the CSS Device Adaption spec changed hands, so
I am adding the new editors to this thread.

Cheers,
Kenneth

On Mon, May 14, 2012 at 4:25 PM, John Mellor <johnme@chromium.org> wrote:
> I wrote a set of test pages to determine what browsers support
> these: jsbin.com/uyojoj/2
>
> And tested using the following browser versions:
> - (Legacy) Android Browser on Nexus S running ICS 4.0.4
> - Chrome for Android beta 2 on Nexus S running ICS 4.0.4
> - Firefox Aurora 14.0a2 (2012-05-13) on Nexus S running ICS 4.0.4
> - Internet Explorer Mobile 9 on Nokia Lumia 800 running WP7.5
> - Nokia Browser for N9 on Nokia N9 running MeeGo 1.2 Harmattan
> - Opera Mobile 12.00.ADR-1204201824 on Nexus S running ICS 4.0.4
> - Mobile Safari on iPod touch (4th gen) running iOS 5.1.1
>
> Here are the viewport widths that the browsers calculated on the 4 test
> pages:
>
> Test: \ Browser:|Android|Chrome |Firefox|  IE   | Nokia | Opera |Safari |
> ----------------+-------+-------+-------+-------+-------+-------+-------+
> Default         |  980  |  980  |  800? | 1024  |  980  |  980? |  980  |
> XHTML-MP        |  320  |  320  |  320  |  320  |  320  |  320  |  320  |
> HandheldFriendly|  320  |  320  |  800? |  320  |  320  |  980? |  980  |
> MobileOptimized |  320  |  320  |  800? |  320  |  320  |  980? |  980  |
>
> (there are question marks next to the Firefox and Opera widths since
> window.innerWidth did not match the observed viewport width, so I had to
> estimate these by eye)
>
> It seems that all browsers already treat the XHTML-MP doctype as equivalent
> to a width=device-width viewport, so I agree with Kenneth that it would make
> sense for the Device Adaptation spec to explicitly formalize this defacto
> standard in a normative section.
>
> Handling of legacy HandheldFriendly and MobileOptimized viewport tags is
> less consistent, but adding these to the specification could also be useful,
> to improve interoperability.
>
> In both cases the order of precedence Kenneth suggested (whereby modern
> standards override legacy ones, irrespective of document order) seems wise,
> as it reduces the risk of supporting the legacy methods.
>
> Cheers,
> John
>
>
> On Wed, May 9, 2012 at 11:49 AM, Kenneth Rohde Christiansen
> <kenneth.christiansen@gmail.com> wrote:
>>
>> Hi there,
>>
>> Following a discussion on webkit-dev [1], we would like to have added
>> a nomative section in the CSS Device Adaptation spec [2], specifying
>> how to handle legacy viewport tags, such as HandheldFriendly.
>>
>> The spec already briefly talks about XHTML-MP in the following:
>>
>> "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."
>>
>> The Nokia N9 browser, WP7 Internet Explorer and Android already
>> implement such support. And testing shows that iOS at least does
>> similar things for XHTML-MP.
>>
>> The IE team even has a blog post explaining how it works [3]
>>
>> Basically there is a priority:
>>
>> XHTML-MP doctype (overrides default configuration)
>> HandheldFriendly meta tag (overrides XHTML-MP doctype)
>> MobileOptimized (overrides HandheldFriendly, etc)
>> viewport (overrides MobileOptimized etc)
>>
>> The XHTML-MP doctype would correspond to the following viewport meta
>> tag: <meta name="viewport" content="width=device-width,
>> height=device-height, initial-scale=1">
>>
>> The same counts for HandheldFriendly (and MobileOptimized, in the case
>> the content attribute is missing or not parseable)
>>
>> Else <meta name="MobileOptimized" content="320"> would to correspond
>> to  <meta name="viewport" content="width=320, initial-scale=1">
>>
>> Cheers,
>> Kenneth
>>
>> [1] http://thread.gmane.org/gmane.os.opendarwin.webkit.devel/20536
>> [2] http://www.w3.org/TR/css-device-adapt/
>> [3]
>> http://blogs.msdn.com/b/iemobile/archive/2010/11/22/the-ie-mobile-viewport-on-windows-phone-7.aspx
>>
>> --
>> 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 ﹆﹆﹆
>
>



-- 
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 ﹆﹆﹆
Received on Thursday, 24 May 2012 23:01:38 GMT

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