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Re: XHTML 2.0 - dfn : Content model and usability (PR#7832)

From: Laurens Holst <lholst@students.cs.uu.nl>
Date: Sat, 25 Mar 2006 13:43:18 +0100
Message-ID: <44253AE6.4000107@students.cs.uu.nl>
To: "'www-html@w3.org'" <www-html@w3.org>
Jukka K. Korpela schreef:
>> According to my studies it's used in around 0.1% of the Web's pages. One
>> in every thousand pages isn't bad, given how few pages could be expected
>> to be defining terms; In particular, it's used more than <ins>, <del>,
>> <var>, <samp>, <bdo>, etc.
> I can't argue with your statistics - the Google analysis
> http://code.google.com/webstats/2005-12/elements.html
> does not cover the <dfn> element. But I think I have almost never seen 
> <dfn> used anywhere except on my own pages and on sites like W3C (and 
> tutorials that describe the <dfn> element and illustrate its use) - 
> and I have read other people's HTML code quite a lot.
> Assuming that the figure 0.1% is representative, is it small or large 
> as compared with the expected frequency of pages that actually contain 
> definitions of terms? After all, what matters - for purposes like 
> developing browsers and search engines - is the probability that you 
> can actually locate defining occurrences by looking at markup for them
> (at present, <dfn> and <dt>). Even if you get a large amount of 
> information that way, is it enough if it is just a small fraction of 
> pages that actually define things?

Maybe on regular websites it isn’t used often, but I have been writing 
technical documentation in XHTML 2.0, and there having the <dfn> element 
has been very useful. Not having definitions marked up as such would be 
providing the user with a lesser reading experience.

Dfn might not have the ability to automatically extract the definition 
itself (but that would probably be difficult anyway, given that 
definitions appear in different forms and different context, and not 
always something you can easily mark up and take out of context), but it 
does give the capability to automatically create an index, and even 
though we don’t use that currently it’s an interesting application of 
dfn as well.

Imho, whether it is actually being used on the web is of very *very* 
little concern. If you do that, looking at semantic markup as a whole 
would also lead you to the conclusion that it’s not being used often 
enough, and thus pointless. (Google’s frequency analysis is imho 
interesting, but not very useful beyond that.) Look at a random 
technical book, e.g. Data Structures and Algorithms in Java by Goodrich 
and Tamassia, and you’ll see examples of marked up defining instances on 
almost every page.

Dfn is necessary for XHTML to be a mature document format which can be 
used in professional applications. XHTML is NOT just a language to 
create websites, it is a language for /documents/, and it needs the 
facilities to write them properly with all the common typographical 
structures expressed semantically.


Ushiko-san! Kimi wa doushite, Ushiko-san!!
Laurens Holst, student, university of Utrecht, the Netherlands.
Website: www.grauw.nl. Backbase employee; www.backbase.com.

Received on Saturday, 25 March 2006 12:47:13 UTC

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