http://www8.zdnet.com/macweek/mw_1129/op_dinucci.html
JULY 23, 1997
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VOLUME 11 ISSUE 29
DESIGNING THE WEB DARCY DINUCCI
XML: A return to traditional standards might save the day
The first public draft of HTML 4.0, posted by the World Wide Web Consortium
(W3C) earlier this month, is distinctly underwhelming. When it is finally
approved, HTML 4.0 will codify features that are already supported in
Netscape Communicator and Microsoft Internet Explorer, such as frames,
style sheets and the Object tag. It will also add new features for tables,
forms, math layouts and accessibility.
These are solid, important additions, but Web designers can be forgiven for
wishing that the W3C had bit off a little more. It's a tough dilemma:
Centralized management of HTML by a disinterested standards body is crucial
to the Web's development, but the consensus process is painfully slow.
Miraculously, the solution is actually at hand. To find it, just dig a
little deeper in the W3C's publications. It's called Extensible Markup
Language, or XML, and it could open the door to a flood of useful new tags.
SGML: The elder standard
XML is based on Standard Generalized Markup Language (SGML), the mother of
all text markup languages, which was codified by the International
Organization for Standardization (better known as ISO) more than a decade
ago. HTML is an example of SGML in action - an SGML application created by
Tim Berners-Lee for the first Web pages.
The example illustrates just how flexible SGML is. To create a new tag
language, publishers simply create a document type definition (DTD) that
defines the language and its tags. SGML-capable software knows how to read
the DTD and applies the rules described to render the file.
read any SGML type, not just HTML. Unfortunately, SGML was just too hard to
use and support, and it failed to win a following. Chastened but not
defeated, the SGML partisans regrouped and have since streamlined the
language and adapted it for use over networks. The result is XML.
Do-it-yourself markup language
When support for XML is in place, every publisher will theoretically be
able to create tags by simply adding them to a document. You won't even
need to create a DTD; style sheets or scripts can tell the browser how to
treat each element.
The value of XML will be felt most keenly by industries such as banking or
health care, which will be able to create tags and DTDs to structure and
process the kind of specialized information that, at the current rate,
would make it into the HTML spec sometime in the middle of the next
millennium.
Designers of simpler publications can always just stick with HTML, but
imagine being able to create a tagging system that describes your
publication's structure and can then be used to build indexes that are
really meaningful to your audience.
All this is a way off: The XML spec itself is still just a working draft at
the W3C. But XML is already being built into the next browsers from
Microsoft and Netscape, and by this time next year designers should be able
to stop grousing about HTML's slow progress and see how it feels to create
their own tags.
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Darcy DiNucci (darcy@tothepoint.com) is co-author of "Elements of Web
Design." She consults on electronic information design from her office in
San Francisco.
--- Rohit Khare /// MCI Internet Architecture (BOS) /// khare@mci.net Voice+Pager: (617) 960-5131 VNet: 370-5131 Fax: (617) 960-1009