It is important that browsers properly ignore tags that they do not
understand. The HTML DTD is extensible with additional tags for purposes
of specialist browsers, e.g. for versioning.
So-called 'strict' checking for unknown tags must always be an option
so that maximum downwards compatibility is maintained.
This is not a question of what extensions become 'standards' but rather
of the importance of downwards compatibility. Documents may well contain
information that is of relevance to the specialiast functionality of some
browsers and irrelevant to others. It is important that the such documents
can be viewed with all browsers.
b.
Brian Gaines Knowledge Science Institute, University of Calgary
gaines@cpsc.ucalgary.ca Calgary, Alberta, Canada T2N 1N4
http://ksi.cpsc.ucalgary.ca/KSI/KSI.html