Despite all the semantics it really does make a difference to this
argument that IE does not recognise and treat correctly <abbr> but does
recognise and treat correctly <acronym>. The mouseover will display a
tooltip. It also makes a difference that <acronym> has been dropped from
the proposals for XHTML 2.0. Other browsers treat each correctly.

So the pragmatic approach would be to use <acronym> for both acronyms
and abbreviations for all documents, although it is not semantically
correct, and then when it is practicable to change the !DOCTYPE
declaration for XHTML 2.0 do a global search and replace for <acronym>
to <abbr>.

John

John Colby
Lecturer, School of Computing, Faculty of Computing, Information and
English
Room F328a, Feeney Building, University of Central England,
Franchise Street, Perry Barr, Birmingham B42 2SU
Tel: +44 (0) 121 331 6937, Fax +44 (0) 121 331 6281, Mobile: 0771 114
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