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Is 1.3.5 underrated?

From: Bailey, Bruce <Bruce.Bailey@ed.gov>
Date: Tue, 13 Dec 2005 10:38:42 -0500
Message-ID: <CCDBDCBFA650F74AA88830D4BACDBAB50AED31C1@wdcrobe2m02.ed.gov>
To: "Guide Lines list" <w3c-wai-gl@w3.org>

This has come up before, but I could not locate a comprehensive dialog / summary / conclusion.  Please feel free to provide a URL and optional chastisement if I missed it.

The requirement for a logical reading order is contained in two checkpoints from WCAG 1.0:

5.3:  Do not use tables for layout unless the table makes sense when linearized.  Otherwise, if the table does not make sense, provide an alternative equivalent (which may be a linearized version).  [Priority 2]

6.1:  Organize documents so they may be read without style sheets.  For example, when an HTML document is rendered without associated style sheets, it must still be possible to read the document.  [Priority 1.  A sufficient scrambled reading order, probably owing to CSS used for layout without consideration of the order of content in source, is generally held to be a violation of this checkpoint.]

The requirement for a logical reading order is reflected only by one WCAG 2.0 success criteria:

1.3.5:  When content is arranged in a sequence that affects its meaning, that sequence can be programmatically determined.  [Level 3]

I have a two big concerns with this:

(1)  The priority level seems way too low.  How is the requirement for a logical reading order not justified at level 1?  I would argue that this is a huge barrier to accessibility for web content like Flash and PDF.

(2)  The associated Common Failures examples make it clear that possible problems captured by WCAG 1.0 checkpoints 5.3 and 6.1 *are* meant to be addressed by success criteria 1.3.5.  As written, IMHO, it does not do so explicitly.

I suggest borrowing some of the "intent" wording for the sc (still using "programmatically determined"):

When content is arranged in a sequence that affects its meaning, it must be possible to programmatically determine at least one sequence of the content that makes sense.

But "makes sense" is also too soft, so dipping into intent once more:

When content is arranged in a sequence that affects its meaning, it must be possible to programmatically determine at least one sequence of the content that preserves a reading order needed to perceive meaning.

I don't care for starting success criteria with "When", so I will also offer up the last wording my little group arrived at for documents:

A logical reading order that includes all visual elements required for comprehension shall be specified by the underlying structure.

(3)  Tangentially, does WCAG 2.0 forbid layout tables in HTML, and if so, at what level?  The earlier mapping document tied layout tables only to 4.1 (use technologies according to specification) which currently only has 4.1.1 (parsed unambiguously) which is not the same thing at all.
Received on Tuesday, 13 December 2005 15:38:48 GMT

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