[whatwg] Semantics of the dfn and abbr Elements

Lachlan Hunt lachlan.hunt at lachy.id.au
Thu Oct 13 09:19:02 PDT 2005

   Just a few issues regarding the use of abbr and dfn elements.

*The abbr Element's title Attribute*

I think the title attribute should also be allowed to be omitted from 
the abbr element if there is another abbr element with a title attribute 
for the same abbreviation in the document.  This would be very useful 
for cases where the same abbreviation is used multiple times, but is not 
defined (using <dfn>) anywhere in the document.

*Multiple Definitions for the Same Term*

What happens if there are multiple definitions for the same 
abbreviation?  For example, if the same abbreviation has two different 
expansions given with two different meanings.  Which one would an <abbr> 
element without a title attribute be associated with?

"HTML" can have more than one meaning in different contexts.

   <p><dfn><abbr title="Hypertext Markup Language">HTML</abbr></dfn> is 
a markup language for ...</p>
   <p>... <abbr>HTML</abbr> ...<p> (1)

   <p><dfn><abbr title="High Temperature Materials 
Laboratory">HTML</abbr></dfn> is something else...</p>
   <p>... <abbr>HTML</abbr> ...<p> (2)

<p>... <abbr>HTML</abbr> ...<p> (3)

(That could easily happen in a news site, for example.  Not necessarily 
with "HTML", but, obviously, there's lots of words and abbreviations 
with multiple meanings.)

Should it be defined to always be the first defining instance occurring 
in document order?  Or, probably better, should it the first or the 
nearest occurrence of the defining instance sharing a common ancestor 
sectioning element as the abbreviation?

So, does (1) stand for "Hypertext Markup Language"?  Does (2) stand for 
"High Temperature Materials Laboratory"?  What does (3) stand for?

*Definitions with Links*

If the dfn element contains a hyperlink, as in either:
   <dfn><abbr><a href="">HTML</a></abbr></dfn>
   <dfn><a href=""><abbr>HTML</abbr></a></dfn>

it should be defined as being as a link to either the term's definition 
or supplementary information about the term and/or its defintion.

For example, a paragraph may contain a simple definition for the term 
with the link to the Wikipedia entry for more information.

<p><abbr title="..."><a 
href="http://en.wikipedia.org/wiki/HTML">HTML</a></abbr> is a semantic 
language for marking up documents published on the web.</p>

Lachlan Hunt

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