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[xhtml2] role/property/class differences

From: <karl@w3.org>
Date: Thu, 17 Aug 2006 03:27:28 -0000
To: www-html-editor@w3.org
Message-Id: <20060817032734.C8B8F4F581@homer.w3.org>

This is a QA Review comment for "XHTML 2.0"
8th WD

About http://www.w3.org/TR/2006/WD-xhtml2-20060726/mod-roleAttribute.html#s_roleAttributemodule

There will be confusion in the community about the exact usage of role, property and class which seem to cover very similar goal. Reading the specification, a few times it's still not clear what are the abstract definition of each of them

	role = QNames
	This attribute describes the role(s) the current 
	element plays in the context of the document. It 
	is used by applications and assistive technologies 
	to determine the purpose of UI widgets.

	property = QName
	This attribute indicates which property is being 
	defined by the element. If it is not specified, 
	the property is reference.

	class = NMTOKENS
	This attribute assigns one or more class names to 
	an element; the element may be said to belong to 
	these classes. A class name may be shared by 
	several element instances.
	rel = QName
	This attribute describes the relationship between 
	the resource specified by the about attribute 
	(or its default value) and the resource referred 
	to by the href attribute.

The way it is said in the specification, it leads to believe that 

role       is for    widgets/behaviour
property   is for    semantics
class      is for    style?
rel/rev    is for    relationship between documents.

Many attributes with definition which seems to be overlapping sometimes.

But it makes it a little bit awkward to have property and class. class is already use for semantics in the microformats community and in many cases outside of this community. Why not giving the definition of property to the class attributes, will it create specific problems?

In the wiki page http://microformats.org/wiki/hcalendar-example1-steps

assume that "class <=> property"

<p class="vevent" href="http://www.web2con.com/">
  <span class="summary">Web 2.0 Conference</span>: 
  <span class="dtstart" content="2005-10-05">October 5</span>-
  <span class="dtend" content="2005-10-08">7</span>,
 at the <span class="location">Argent Hotel, San Francisco, CA</span>

The content attribute here solves an abuse by the microformat community which puts accessibility users at risk.

Karl Dubost - http://www.w3.org/People/karl/
W3C Conformance Manager, QA Activity Lead
   QA Weblog - http://www.w3.org/QA/
      *** Be Strict To Be Cool ***
Received on Thursday, 17 August 2006 03:28:58 UTC

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