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Re: fear of "invisible metadata"

From: Laura Carlson <laura.lee.carlson@gmail.com>
Date: Mon, 18 Jun 2007 14:51:30 -0500
Message-ID: <1c8dbcaa0706181251p247444cdk6dcbae8a6f807d5b@mail.gmail.com>
To: public-html@w3.org

Empty summary attributes are acceptable in WCAG 2.0 on layout tables,
but not recommended (W3C WCAG 2.0 [1]):

> F46: Failure of SC 1.3.1 due to using th elements, caption elements,
> or non-empty summary attributes in layout tables
>
> The objective of this technique is to describe a failure that occurs
> when a table used only for layout includes either th elements, a
> summary attribute, or a caption element. This is a failure because it
> uses structural (or semantic) markup only for presentation. The
> intent of the HTML table element is to present data.
>
> Although not commonly used in a layout table, the following
> structural markup would also be failures of Success Criterion 1.3.1
> if used in a layout table:
>
> * headers attributes
> * scope attributes [LC-679]
>
> Assistive technologies use the structure of an HTML table to present
> data to the user in a logical manner. The th element is used to mark
> the column and row headers of the table. A screen reader uses the
> information in th elements to speak the header information that
> changes as the user navigates the table. The summary attribute on the
> table element provides a textual description of the table that
> describes its purpose and function. Assistive technologies make the
> summary attribute information available to users. The caption element
> is part of the table and identifies the table.
>
> Although WCAG 2 does not prohibit the use of layout tables, CSS-based
> layouts are recommended in order to retain the defined semantic
> meaning of the HTML table elements and to conform to the coding
> practice of separating presentation from content. [LC-1407] When a
> table is used for layout purposes the th element should not be used.
> Since the table is not presenting data there is no need to mark any
> cells as column or row headers. Likewise, there is no need for an
> additional description of a table which is only used to layout
> content. Do not include a summary attribute and do not use the
> summary attribute to describe the table as, for instance, "layout
> table". When spoken, this information does not provide value and will
> only distract users navigating the content via a screen reader. Empty
> summary attributes are acceptable on layout tables, but not
> recommended.

But I agree with Gregory, if any element should be deprecated as a
visual construct and relegated to CSS it is table for layout purposes.

fyi...WCAG Samurai bans tables for layout. [2]

> Guideline 5. Create tables that transform gracefully
>
> * Do not use tables for layout.
> * The use of summary, caption, and abbreviations for headers is
> covered by Guideline 3. Use those elements and attributes if
> necessitated by your content.

[1] http://www.w3.org/TR/WCAG20-TECHS/#F46
[2] http://wcagsamurai.org/errata/errata.html

Best Regards,
Laura
Received on Monday, 18 June 2007 19:51:34 UTC

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