[Bug 18574] New: @hidden should have a weak mapping to aria-hidden=true


           Summary: @hidden should have a weak mapping to aria-hidden=true
           Product: HTML WG
           Version: unspecified
          Platform: PC
               URL: http://dev.w3.org/html5/spec/wai-aria.html#table-aria-
        OS/Version: All
            Status: NEW
          Keywords: a11y
          Severity: normal
          Priority: P3
         Component: HTML5 spec
        AssignedTo: dave.null@w3.org
        ReportedBy: xn--mlform-iua@xn--mlform-iua.no
         QAContact: public-html-bugzilla@w3.org
                CC: mike@w3.org, public-html-wg-issue-tracking@w3.org,

Disambiguate @hidden from @aria-hidden=true. @hidden is currently  listed in
HTML5's strong ARIA mappings table. It should rather be in the ha weak mapping

The strong mapping table currently says about the hidden attribute that: [1] 

1. "The Strong native semantics and default implied ARIA semantics"
2.  for an "Element with a hidden attribute"
3.  is "The aria-hidden state set to "true".

Similarly, the table says about the empty alt attribute:

1. "The Strong native semantics and default implied ARIA semantics"
2. for an "img element whose alt attribute's value is empty"
2. is "presentation role"

Now: We know that the empty alt attribute causes screenreaders to interpret the
image as presentational in a very literal sense. [2]  Hence, one could expect
that @hidden as well would be mapped to its correspoding aria attribute quite

However, as of yet, no such correspondence is documented - @hidden does
seemingly not map whether to A11Y APIs or to WAI-ARIA. [3]  And if @hidden had
been a direct synonym for @aria-hidden=true in the same way that the empty
alt="" is a synonym for role=presentation, then one would have expected the
following paragraph to be  _hidden_ from AT:

   <p hidden style="display:block">Lorem ipsum

However, no ATs hide the above paragraph from users. Because it turns out that
there are currently no difference, to ATs, between @style="display:none" and

In addition, the issue of ISSUE 204, is about allowing ATs to "jump around"
inside a section that that has been hidden with the @hidden attribute.  So what
if that section - or a nested section inside that section - has
aria-hidden=true? Would AT then see it? Example:

   <p hidden style="display:block" aria-hidden="true" id=D >Lorem ipsum

Currently, at least, thy would not see the above. And for that reason, one
should assume that if @aria-describedby="D" pointed to the above example, then
ATs would not perceive it as a "rich" description - but would rather read it as
a "flattened" description. (This _could_ be a feature in itself, e.g. if the
author wants to make sure that the section is flattened to all AT suers.)

The weak ARIA mapping table is for  semantivs that can be overridden: "Some
HTML elements have native semantics that can be overridden". And I think that
current status - and the outcome of ISSUE-204, indicates that the weeak table
is more correct.

[0] http://dev.w3.org/html5/spec/wai-aria.html#table-aria-weak
[1] http://dev.w3.org/html5/spec/wai-aria.html#table-aria-strong
[2] http://dvcs.w3.org/hg/html-api-map/raw-file/default/Overview.html#el-59
[3] http://dvcs.w3.org/hg/html-api-map/raw-file/default/Overview.html#att-22

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Received on Wednesday, 15 August 2012 11:58:41 UTC