Re: change proposal for <main>: possible validation warning heuristic for misuse

On Dec 1, 2012, at 3:27 PM, Silvia Pfeiffer <silviapfeiffer1@gmail.com> wrote:

> 
> 
> On Sun, Dec 2, 2012 at 9:19 AM, Maciej Stachowiak <mjs@apple.com> wrote:
> 
> <chair hat off>
> 
> Hello Steve & James,
> 
> One concern raised by WebKit contributors was that <main> could end up getting frequently misused, and as a result, could harm accessibility. James's conformance rules will slightly reduce misuse, but probably not eliminate it. However, if these plus the current conformance rules capture the scenarios of misuse, how about making <main> not have an implied role=main in these cases? In other words, make it affect implementation behavior as well as conformance. This would significantly reduce the potential downsides of <main>, I think. And in the case where you truly need to violate these rules to mark the main content, you can always use an explicit role=main.
> 
> 
> Not sure about this one.

I think this will be a lot more effective at limiting the harm from potential improper use of <main> than a conformance error. A conformance error is a discouragement for some authors, but most content is non-conforming. Meanwhile, implementation behavior can avoid incorrectly identifying the main content even in the face of authors who do not prioritize document conformance.

> 
> 
> Another related thought: if the rule for finding the main content becomes a little more involved based on the above rules, then perhaps the spec could document how to find the main content when no <main> element or role=main is present. This would end up documenting the semi-mythical "Scooby Doo algorithm" for cases when the <main> element is absent. I think a unified "find the main content algorithm" applying these sets of rules would be really helpful to accessibility, it would help make clear why an explicit element is helpful even with a fallback approach, and it would clarify that the two need not conflict.
> 
> I agree with this suggestion. I would also like to see "Scooby Doo" documented properly. I do wonder, however, since (if?) it is only accessibility related, whether it should be in the HTML spec, or in the mapping spec of Stever, or in a WCAG spec.

I think a "find the main content" algorithm has non-accessibility uses as well, for example for data mining tools, or for "readability" style tools or browser features.

I did think about the idea of putting it in the HTML spec, but then the <main> element spec would have to patch/replace this algorithm to correctly handle the <main> element.

Regards,
Maciej