The PRE Element and Accessibility (1 of 3 LONG)

[Janina Sajka]

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."