The PRE Element and Accessibility (1 of 3 LONG)

[Charles Crawford]

So are you supporting the continuation of PRE?
On Sun, 31 Aug 2003, Janina 
Sajka wrote:

> I have promised a dissertation on the <pre> element vis a vis
> accessibility. This email is that document.
> 
> DISCLAIMER:All opinions expressed here are my own and do not necessarily
> reflect the views of any other individual or of any organization except
> as expressly denoted within quotation marks and attributed by URL
> reference.
> 
> The Issue: There have been recent exchanges contesting whether or not
> use of the <pre> tag constitutes a challenge to accessibility of that
> content.
> 
> DEFINITION: <pre> has been in the HTML specs at least since HTML 2.0
> (see http://www.w3.org/MarkUp/html-spec/html-spec_5.html) where <pre>
> was defined (see
> http://www.w3.org/MarkUp/1995-archive/Elements/PRE.html) as:
> 
> "PRE: Preformatted text
> 
>    "Preformatted elements in HTML are displayed with text in a fixed
>    width font, and so are suitable for text which has been formatted for
>    a teletype by some existing formatting system."
> 
> Note: There wasn't really an html 1.0 (See
> http://lists.w3.org/Archives/Public/www-html/1997Jan/0035.html).
> 
> The definition from HTML 4.01 (see
> http://www.w3.org/TR/html401/struct/text.html) explains:
> 
>    ""The PRE element tells visual user agents that the enclosed text
>    is "preformatted". When handling preformatted text, visual user
>    agents:
>      * ""May leave white space intact.
>      * "May render text with a fixed-pitch font.
>      * "May disable automatic word wrap.
>      * "Must not disable bidirectional processing.
> 
>    "Non-visual user agents are not required to respect extra white
>    space in the content of a PRE element. ...
> 
>    "The DTD fragment above indicates which elements may not appear
> within
>    a PRE declaration. This is the same as in HTML 3.2, and is
>    intended to preserve constant line spacing and column alignment for
>    text rendered in a fixed pitch font. Authors are discouraged from
>    altering this behavior through style sheets."
> 
> <PRE> is still available in the most recent W3C XHTML 1.1 
> recommendation (see http://www.w3.org/TR/xhtml11/) and in the public
> draft for XHTML 2.0 (see
> http://www.w3.org/TR/2002/WD-xhtml2-20020805/xhtml2.html).
> 
> ACCESSIBILITY
> 
> The W3C's recommendation on accessibility in content markup is known as
> the Web Content Accessibility Guidelines (WCAG). The WCAG 1.0
> recommendation is at http://www.w3.org/TR/WCAG10/.
> The current public draft of WCAG 2.0 is at
> http://www.w3.org/TR/2003/WD-WCAG20-20030624/. 
> 
> The approach to accessibility in web content is introduced in the WCAG
> 1.0 as follows:
> 
> "For those unfamiliar with accessibility issues pertaining to Web page
>    design, consider that many users may be operating in contexts very
>    different from your own:
>      * "They may not be able to see, hear, move, or may not be able to
>        process some types of information easily or at all.
>      * "They may have difficulty reading or comprehending text.
>      * "They may not have or be able to use a keyboard or mouse.
>      * "They may have a text-only screen, a small screen, or a slow
>        Internet connection.
>      * "They may not speak or understand fluently the language in which
>        the document is written.
>      * "They may be in a situation where their eyes, ears, or hands are
>        busy or interfered with (e.g., driving to work, working in a loud
>        environment, etc.).
>      * "They may have an early version of a browser, a different browser
>        entirely, a voice browser, or a different operating system.
> 
>    "Content developers must consider these different situations during
>    page design. While there are several situations to consider, each
>    accessible design choice generally benefits several disability groups
>    at once and the Web community as a whole. For example, by using
>    style sheets to control font styles and eliminating the FONT
>    element, HTML authors will have more control over their pages, make
>    those pages more accessible to people with low vision, and by sharing
>    the style sheets, will often shorten page download times for all
>    users."
>  
> The WCAG summarizes the process as consisting of twh themes:
> 
> "
>    The guidelines address two general themes: ensuring graceful
>    transformation, and making content understandable and navigable."
> 
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-- 
-- Charlie Crawford