It's not Latin, but HTML has reached middle age in standard
Version 4.01. The W3C has no plans to develop another version and has officially
said so. Rather, HTML is being subsumed and modularized as an Extensible Markup
Language (XML). Its new name is XHTML, Extensible Hypertext Markup Language.
The emergence of XHTML is just another chapter in the often
tumultuous history of HTML and the Web, where confusion for authors is the norm,
not the exception. At the worst point, the elders of the World Wide Web
Consortium (W3C) responsible for accepted and acceptable uses of the language --
i.e., standards -- lost control of the language in the browser "wars" between
Netscape and Microsoft. The abortive HTML+ standard never got off the ground,
and HTML 3.0 became so bogged down in debate that the W3C simply shelved the
entire draft standard. HTML 3.0 never happened, despite what some opportunistic
marketers claimed in their literature. Instead, by late 1996, the browser
manufacturers convinced the W3C to release HTML standard Version 3.2, which for
all intents and purposes simply standardized most of Netscape's HTML extensions.
Netscape's dominance as the leading browser, as well as a
leader in Web technologies, faded by the end of the millennium. By then,
Microsoft had effectively bundled Internet Explorer into
the Windows operating system, not only as an installed application, but also as
a dominant feature of the GUI desktop. And, too, Internet Explorer introduced
several features (albeit nonstandard at the time) that appealed principally to
the growing Internet business and marketing community.
Fortunately for those of us who appreciate and strongly support
standards, the W3C took back its primacy role with HTML 4.0, which stands today
as HTML Version 4.01, released in December 1999. Absorbing many of the Netscape and Internet Explorer
innovations, the standard is clearer and cleaner than any previous ones,
establishes solid implementation models for consistency across browsers and
platforms, provides strong support and incentives for the companion Cascading
Style Sheets (CSS) standard for HTML-based displays, and makes provisions for
alternative (nonvisual) user agents, as well as for more universal language
supports.
Cleaner and clearer aside, the W3C realized that HTML could
never keep up with the demands of the web community for more ways to distribute,
process, and display documents. HTML offers only a limited set of
document-creation primitives and is hopelessly incapable of handling
nontraditional content like chemical formulae, musical notation, or mathematical
expressions. Nor can it well support alternative display media, such as handheld
computers or intelligent cellular phones.
To address these demands, the W3C developed the XML standard.
XML provides a way to create new, standards-based markup languages that don't
take an act of the W3C to implement. XML-compliant languages deliver information
that can be parsed, processed, displayed, sliced, and diced by the many
different communication technologies that have emerged since the Web sparked the
digital communication revolution a decade ago. XHTML is HTML reformulated to
adhere to the XML standard. It is the foundation language for the future of the
Web.
Why not just drop HTML for XHTML? For many reasons. First and
foremost, XHTML has not exactly taken the Web by storm. There's just too much
current investment in HTML-based documentation and expertise for that to happen
anytime soon. Besides, XHTML is HTML 4.01 reformulated as an application of XML.
Know HTML 4 and you're all ready for the future.
Deprecated Features
One of the unpopular
things standards-bearers have to do is make choices between popular and proper.
The authors of the HTML and XHTML standards exercise that responsibility by
"deprecating" those features of the language that interfere in the grand scheme
of things.
For instance, the <center> tag tells the browser
to display the enclosed text centered in the display window. But the CSS
standard provides ways to center text, too. The W3C chooses to support the CSS
way and discourages the use of <center> by deprecating the tag.
The plan is, in some later standard version, to stop using
<center> and other deprecated elements and attributes of the
language.
Throughout the book, we specially note and continuously remind
you when an HTML tag or other component is deprecated in the current standards.
Should you stop using them now? Yes and no.
Yes, because there is a preferred and perhaps better way to
accomplish the same thing. By exercising that alternative, you ensure that your
documents will survive for many years to come on the Web. And, yes, because the
tools you may use to prepare HTML/XHTML documents probably adhere to the
preferred standard. You may not have a choice, unless you disable your tools. In
any event, unless you hand-compose all your documents, you'll need to know how
the preferred way works so that you can identify the code and modify it.
However compelling the reasons for not using deprecated
elements and attributes are, they still are part of the standards. They remain
well supported by most browsers and aren't expected to disappear any time soon.
In fact, since there is no plan to change the HTML standard, the "deprecated"
stamp is very misleading.
So, no, you don't have to worry about deprecated HTML features.
There is no reason to panic, certainly. We encourage you to use and continue to
use them, since the deprecated features typically are simpler and eminently more
human-readable than their alternatives.
A Definitive Guide
The paradox in all this is that even the HTML 4.01 standard is not the definitive resource.
There are many more features of HTML in popular use and supported by the popular
browsers than are included in the latest language standard. And there are many
parts of the standards that are ignored. We promise you, things can get
downright confusing.
We've managed to sort things out for you, though, so you don't
have to sweat over what works and doesn't work with what browser. This book,
therefore, is the definitive guide to HTML and XHTML. We give details for all
the elements of the HTML 4.01 and XHTML 1.0 standards, plus the variety of
interesting and useful extensions to the language -- some proposed standards --
that the popular browser manufacturers have chosen to include in their products,
such as:
-
Cascading Style Sheets
-
Java and JavaScript
-
Layers
-
Multiple columns
And while we tell you about each and every feature of the
language, standard or not, we also tell you which browsers or different versions
of the same browser implement a particular extension and which don't. That's
critical knowledge when you want to create web pages that take advantage of the
latest version of Netscape versus pages that are accessible to the larger number
of people using Internet Explorer or even Lynx, a once-popular text-only browser
for Unix systems.
In addition, there are a few things that are closely related
but not directly part of HTML. For example, we touch, but do not handle,
JavaScript, CGI, and Java programming. They all work closely with HTML documents
and run with or alongside browsers, but they are not part of the language
itself, so we don't delve into them. Besides, they are comprehensive topics that
deserve their own books, such as JavaScript: The Definitive Guide, by David
Flanagan, CGI Programming with Perl, by Scott
Guelich, Shishir Gundavaram, and Gunther Birzneiks, Cascading Style Sheets: The
Definitive Guide, by Eric Meyer, and Learning
Java, by Pat Niemeyer and Jonathan Knudsen (all published by O'Reilly).
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