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[Bug 12325] New: Consequences of <table role=presentation> (layout tables)

From: <bugzilla@jessica.w3.org>
Date: Thu, 17 Mar 2011 03:45:54 +0000
To: public-html@w3.org
Message-ID: <bug-12325-2495@http.www.w3.org/Bugs/Public/>
http://www.w3.org/Bugs/Public/show_bug.cgi?id=12325

           Summary: Consequences of <table role=presentation> (layout
                    tables)
           Product: HTML WG
           Version: unspecified
          Platform: PC
               URL: http://dev.w3.org/html5/spec/content-models#annotation
                    s-for-assistive-technology-products-aria
        OS/Version: All
            Status: NEW
          Keywords: aria
          Severity: normal
          Priority: P3
         Component: HTML5 spec (editor: Ian Hickson)
        AssignedTo: ian@hixie.ch
        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,
                    public-html@w3.org


The decision on ISSUE-130 opens up for some meaningless/meaningfull role
changes for the "required owned children" [1][2] of layout tables.

  ISSUES/PROPOSALS:

role=presentation is inherited by table's "Required Owned childen". [1][2] 

1) Therefore <th>, <caption>,  @summary, @headers and @scope, <tfoot> and
<thead> should not occur inside layout tables, as they are meaningless there.
Chances are that a layout table with such features
  a) was not intended as a layout table,  e.g. these features
      (such as <th>,@scope,@headers) are meant for scoping, 
      highlighting and navigation of data tables.
  b) could trigger data table handling in ARIA-unaware legacy AT
  c) could confuse authors, who might think that e.g. @headers will have
effect, wheras in ARIA-supporting AT it is not likely to have effect.
  d) is seldom found in the wild

2) Positively expressed, it is suggested that layout tables may ONLY contain
<table>, <tbody>,<tr>,<td>,<colgroup> and <col>

3) What about changing the ARIA role of table's required owned children? 
    For instance, if <thead> and <tfoot> were permitted inside layout tables,
should one then be allowed to  do <thead role="banner"> or <tfoot
role="contentinfo">? What about changing the role of <td>? 
    PROPOSAL:
    EITHER one should freely be able to change the role of those required owend
children that (per the outcome of this bug) are permitted inside layout tables.
(Though <td role=spinbutton> and similar things might not be meaningful ...). 
    OR one should not be able to change the role of the required owned children
at all. In this case, one would have to add a <header> or a  <footer> instead
of using role=contentinfo and role=banner.

4) PERHAPSES: Should more than a single <tbody> be allowed? Should more than
zero <colgroup> and <col> be allowed? 
    Arguments in favour: 
    - if it helps authors to avoid creating more than one table, then yes. 
    - <col> corresponds to <tr> - logical to have same rules for both.
    - <colgroup> corresponds to <tbody> - logical to have same rules for both.
    Argumetns against: 
    a) layout tables are often - and should be
    b) if  permitted, then why shoudn't we, as well, permit tfoot, thead and
th? 

References:
[1]http://www.w3.org/TR/wai-aria/complete#presentation  
[2] http://www.w3.org/TR/wai-aria/complete#mustContain
[Initial letter]
http://lists.w3.org/Archives/Public/public-html/2011Mar/0332.html

This bug relates to:
http://dev.w3.org/html5/spec/tabular-data#the-table-element
http://dev.w3.org/html5/spec/tabular-data#the-td-element
http://dev.w3.org/html5/spec/tabular-data#the-tbody-element
http://dev.w3.org/html5/spec/tabular-data#the-tr-element
http://dev.w3.org/html5/spec/content-models#annotations-for-assistive-technology-products-aria

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Received on Thursday, 17 March 2011 03:45:55 GMT

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