Re: 分號作為 meta-viewport 的區隔字符（Fwd: Re: [css-device-adapt] Accepting semi-colons as a separator for meta-viewport）

不支持以分号作为分割符，分号应当作为“同一元组不同部分”的分割符，参考HTTP
ACCEPT头的定义，各元组之间使用逗号分割，同元组的Type和Parameter之间用分号分割。这种方式应当是前端界的一种共识，如果现在将分号作为分割，会对未来需要对单一元组引入第二部分时的语法设计产生制约……
在 2011-10-22 半夜12:05，"Kang-Hao (Kenny) Lu" <kennyluck@w3.org>写道：

> **
> 原文討論串：http://lists.w3.org/Archives/Public/www-style/2011Oct /thread#msg652
> （若沒弄錯的話）以下 CSS 工作組的討論是說，Firefox Mobile 與 Android Browser 支持「;」作為 <meta
> name=viewport> 的 content 裡的區隔字符，而 Safari 與 Opera 只支援「,」。
>
> 大家有什麼想法嗎？有用「;」的人要不要舉個手？
>
> Kenny
>
> -------- Original Message --------  Subject: Re: [css-device-adapt]
> Accepting semi-colons as a separator for meta-viewport  Resent-Date: Fri,
> 21 Oct 2011 09:15:46 +0000  Resent-From: www-style@w3.org  Date: Fri, 21
> Oct 2011 11:14:52 +0200  From: Rune Lillesveen <rune@opera.com><rune@opera.com>  Organization:
> Opera Software ASA  To: www-style@w3.org, "Peter Beverloo"
> <beverloo@google.com> <beverloo@google.com>
>
> On Thu, 20 Oct 2011 19:12:01 +0200, Peter Beverloo <beverloo@google.com> <beverloo@google.com>
> wrote:
>
> > The CSS Device Adapt specification defines a parsing algorithm[1] for
> > the meta-element viewport content, which has been based on WebKit's
> > implementation that shipped with iOS4. This algorithm only accepts
> > commas as separators between properties.
>
> First, it's in a non-normative section, and we want UAs to move towards an
> @viewport implementation. That being said, it's there to suggest a mapping
> between viewport meta and @viewport in a transition phase.
>
> > In reality, web authors are using both commas as semi-colons. A wide
> > range of websites, including CNN[2], Flickr[3] and Reddit[4] depend on
> > this behavior, which has led at least Mozilla and Microsoft to
> > implement it and, in case of the latter, write about it[5].
>
> Yes, and they have to add some combination of scale properties to
> compensate for the fact that "width=device-width;" is the same as
> "width=0" in Safari and Opera (see comments for the mentioned sites below).
>
> > I think the specification should adapt to reflect what authors are
> > doing. While it's unfortunate that the divergence between commas and
> > semi-colons happened, it's important for compatibility among mobile
> > browsers.
>
> Two alternative proposed changes:
>
> 1. Keep the algorithm as it is and mention that some implementations
> accept ';' as a separator in addition to ','.
>
> 2. Modify the algorithm to include ';' as a separator and say that it's
> based on the Safari implementation with the ';' added as a recognized
> separator.
>
> > [1] http://dev.w3.org/csswg/css-device-adapt/#parsing-algorithm
> > [2] http://m.cnn.com
>
> Does not give me a viewport meta in Opera.
>
> > [3] http://m.flickr.com
>
> "width=device-width; initial-scale=1.0; maximum-scale=1.0;
> user-scalable=0;"
>
> Works in Safari because the over-constraining scale values cause the width
> to end up at device-width anyway. This would not have worked in Safari or
> Opera: "width=device-width; user-scalable=0;".
>
> > [4] http://www.reddit.com/.compact (or http://m.reddit.com/)
>
> Same as for m.flickr.com.
>
> > [5]
> > http://blogs.msdn.com/b/iemobile/archive/2010/11/22/the-ie-mobile-viewport-on-windows-phone-7.aspx
>
> --
> Rune Lillesveen
> Layout Group Manager
> Core Technology Department
> Opera Software ASA
>
>
>
>