These technologies don't yet impact the daily lives of most
web developers, but almost certainly will in the not-too distant
future. Keep an eye on them !
You don't need to throw away your
HTML editors just yet,
but keep an eye on this HTML-done-right technology...
In contrast to
HTML which describes document
structure and visual presentation, XML describes data in a
human readable format with no indication of how the data is
to be displayed. It is a database-neutral and device-neutral format;
data marked up in XML can be targeted to different devices using
Extensible Style Language (XSL), the subject of a future WDVL article.
Since XML is truly extensible, rather than a fixed set of elements
like HTML, use of XML will eventually eliminate the need for browser
developers and middleware tools to add special HTML tags (extensions).
XML is an ISO compliant subset of
Standard Generalised Markup Language (SGML),
a simple coding language using generic semantics that are
appropriate for representing information from a wide range of domains.
XML is extensible because it is a metalanguage, which enables one
to write a
Document Type Definition (DTD) and define the rules of
the language so the document can be interpreted by the document
receiver. The purpose of XML is to provide an easy to use subset of
SGML that allows for custom tags to be processed. Custom tags will
enable the definition, transmission and interpretation of data
structures between organizations.
The Document Object Model is a platform- and language-neutral
interface that will allow programs and scripts to dynamically
access and update the content, structure and style of documents.
The Document Object Model provides a standard set of objects for
representing HTML and XML documents, a standard model of how
these objects can be combined, and a standard interface for
accessing and manipulating them. Vendors can support the DOM
as an interface to their proprietary data structures and APIs,
and content authors can write to the standard DOM interfaces
rather than product-specific APIs, thus increasing
interoperability on the Web.
