ISSUE-175: Bug 18394 - Encoding Sniffing Algorithm: parent browsing context defines encoding default

Bug 18394 - Encoding Sniffing Algorithm: parent browsing context defines encoding default

State:
CLOSED
Product:
html
Raised by:
Richard Ishida
Opened on:
2012-08-01
Description:
Bugzilla: https://www.w3.org/Bugs/Public/show_bug.cgi?id=18394

Raised by: Leif Halvard Silli

About: http://dev.w3.org/html5/spec/Overview#encoding-sniffing-algorithm


Proposal: Extend the encoding sniffing algorithm[1] with a new,
2nd last step, like so:

#. If the document lives in a 'nested browsing context'[2],
then return the encoding of the 'parent browsing context',
as a parent browsing context dictated default encoding,
and abort these steps.

Bug #3: Justification.

(1) Currently, the HTML5 encoding sniffing algorithm fails to take
account of the fact that, in case the document of a nested browsing
context has not been supplied with encoding information, then Web
browsers[*] do *not* "return an implementation-defined or
user-specified default character encoding" (as HTML5 currently
requires). Web browsers instead return a 'parent browsing
context-defined' character encoding - the encoding of the document in
the parent browsing context.

[*]I did not test the relevant editions of IE - IE8/IE9/IE10 - yet.
But I know that IE6 does not consider the encoding of the parent
browsing context.

(2) By explicitly including the 'parent browsing context encoding
default' into the algorithm, then we make sure that browser applies the
default at the same step.
The problem, right now, is that the browsers that thus far has
implemented the encoding sniffing algorithm's current step 7 (encoding
pattern matching/detection) disagree about whether it should take place
*before* the parent browsing context default is applied — or *after*
the encoding of the parent browsing context has been considered.
The latter approach, which Chrome seems to take, means that step
7 is unlikely to take place at all if the document lives in a nested
browsing context. Firefox 12 (which by default only performs step 7 for
some locales or at user request) and Opera 12 (which - unlike in at
least Opera 10 - applies step 7 for all locales, take the approach that
encoding pattern matching/detection should occur before the locale
default eventually is applied.


For more, see the blog post I wrote in connection with this bug report.[3]

[1] http://dev.w3.org/html5/spec/Overview#encoding-sniffing-algorithm
[2] http://dev.w3.org/html5/spec/Overview#nested-browsing-context
[3] http://målform.no/blog/white-spots-in-html5-s-encoding-sniffing-algorithm
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  1. I18N-ISSUE-175: Bug 18394 - Encoding Sniffing Algorithm: parent browsing context defines encoding default [.Monitor-HTML] (from sysbot+tracker@w3.org on 2012-08-01)

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Addison Phillips <addison@amazon.com>, Chair, Richard Ishida <ishida@w3.org>, Fuqiao Xue <xfq@w3.org>, Atsushi Shimono <atsushi@w3.org>, Staff Contacts
Tracker: documentation, (configuration for this group), originally developed by Dean Jackson, is developed and maintained by the Systems Team <w3t-sys@w3.org>.
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