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Re: 1.4 text in the content is provided in Unicode or sufficient information is provided so that it can be automatically mapped back to Unicode. [X]

From: Wendy A Chisholm <wendy@w3.org>
Date: Tue, 06 Jan 2004 14:48:30 -0500
Message-Id: <>
To: "lisa seeman" <seeman@netvision.net.il>, "'WAI GL'" <w3c-wai-gl@w3.org>

Lisa wrote:
>With BI- directional languages (like Hebrew and Arabic) The Unicode
>mapping of each letter is not enough. You also need to know the
>direction or flow of the letters to be able to decode unambiguously

If I read it correctly, the HTML spec [1] says that if the language is 
specified the characters should be appropriately mapped to Unicode (and 
thus displayed properly) unless languages are mixed together or there is 
some other reason to override the bidirectional algorithm.  In the mixed 
case, providing additional information (such as using the dir or bdo 
attribute in html) is "sufficient information so that [information] can be 
automatically mapped back to unicode" and satisfies this concern, right?

[1] <http://www.w3.org/TR/REC-html40/struct/dirlang.html#adef-dir>

>For example
>A page written using a visual architecture. -The logical flow of the
>letters is backwards.

Nir Dagan writes about visual versus logical coding of Hebrew [2].  He 
suggests providing the content both visually and logically (visually for 
backwards-compatibility and logically for bidi-capable browsers).

[2] Logical or visual? A practical approach to Hebrew content providing

>Or, in another example, Imagine Right to left text with a phone number
>in the middle.
>Numbers work left to right, but a phone number can be have a hyphen in
>the middle which, as it is NOT a number, will be read as right to left -
>inverting the different half of the number with the second half of the

Assuming that the text is marked as Hebrew or "right-to-left" (either with 
the lang attribute or dir attribute on a parent element) and the phone 
number is marked "left-to-right" (either with a lang attribute of a 
left-to-right language or using dir="ltr"), then the phone number should be 
presented in the correct direction.

How well do browsers and assistive technologies support lang 
attribute?  dir attribute? bidirectional algorithm?
Nir Dagan documents support of charset, bidi algorithm, character encoding 
in Explorer 5.0, Tango 3.3.1, Lynx 2.7.2 and 2.8.1, Netscape 4.51, and 
Opera 3.51

Related resources:
1.  Alan Wood's Unicode Resources - Test for Unicode support in Web 
browsers <http://www.alanwood.net/unicode/hebrew.html>
2. Nir Dagan's Standards for Hebrew on the Web - Characters, character 
encodings, and character 
references  <http://www.nirdagan.com/hebrew/standards> linked from "Hebrew 
on the Web" <http://www.nirdagan.com/hebrew/>
3. Unicode FAQ (I was hoping to find more Hebrew-specific questions and 
answers) <http://www.unicode.org/unicode/faq/>
4. Unicode Standard Annex #9 - The Bidirectional Algorithm 

Therefore, I think that the guideline (as written) handles the issue 
appropriately.  I think in techniques we ought to highlight visual versus 
logical coding and link to Nir's essay as well as provide examples of using 
bdo and dir (or at least link to examples in an external resource).

Lisa, if you disagree that the Guideline handles the issues you have 
raised, please propose a specific change to the Guideline that you would 
like to discuss.

Thank you,

wendy a chisholm
world wide web consortium
web accessibility initiative
Received on Tuesday, 6 January 2004 14:48:57 UTC

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