Chapter 1. HTML, XHTML, and the World Wide Web
Though it began as a military experiment and spent its adolescence as
a sandbox for academics and eccentrics, recent events have
transformed the worldwide network of computer networks -- also
known as the Internet -- into a rapidly
growing and wildly diversified community of computer users and
information vendors. Today, you can bump into Internet users of
nearly any and all nationalities, of any and all persuasions, from
serious to frivolous individuals, from businesses to nonprofit
organizations, and from born-again Christian evangelists to
pornographers.
In many ways, the World Wide Web -- the open community of
hypertext-enabled document servers and readers on the
Internet -- is responsible for the meteoric rise in the
network's popularity. You, too, can become a valued member by
contributing: writing HTML and XHTML documents and then making them
available to web surfers worldwide.
Let's climb up the Internet family tree to gain some deeper
insight into its magnificence, not only as an exercise of curiosity,
but to help us better understand just who and what it is we are
dealing with when we go online.
1.1. The Internet, Intranets,and Extranets
Although
popular media accounts are often confused and confusing, the concept
of the Internet really is rather simple. It's a worldwide
collection of computer networks -- a network of
networks -- sharing digital information via a common set of
networking and software protocols. Nearly anyone can connect a
computer to the Internet and immediately communicate with other
computers and users that are on the Net.
Networks are not new to computers. What makes the Internet global
network unique is its worldwide collection of digital
telecommunication links that share a common set of computer-network
technologies, protocols, and applications. So whether you use a PC
with Microsoft Windows 2000 or Linux or have an ancient Apple IIe,
when connected to the Internet, the computers all speak the same
networking language and use functionally identical programs so that
you can exchange information -- even multimedia pictures and
sound -- with someone next door or across the planet.
The common and now quite familiar programs people use to communicate
and distribute their work over the Internet have also found their way
into private and semi-private networks. These so-called
intranets
and
extranets use the same software, applications,
and networking protocols of the Internet. But unlike the Internet,
intranets are private networks, usually unconnected to outside
institutional boundaries and with restricted access to only members
of the institution. Likewise, extranets restrict access, but use the
Internet to provide services to members.
The Internet, on the other hand, seemingly has no restrictions.
Anyone with a computer and the right networking software and
connection can "get on the Net" and begin exchanging
their words, sounds, and pictures with others around the world, day
or night: no membership required. And that's precisely what is
confusing about the Internet.
Like an oriental bazaar, the Internet is not well organized, there
are few content guides, and it can take a lot of time and technical
expertise to tap its full potential.That's because . . .
1.1.1. In the Beginning
The Internet began in the late 1960s as an experiment in the design
of robust computer networks. The goal was to construct a network of
computers that could withstand the loss of several machines without
compromising the ability of the remaining ones to communicate.
Funding came from the U.S. Department of Defense, which had a vested
interest in building information networks that could withstand
nuclear attack.
The resulting network was
a marvelous technical success, but was limited in size and scope. For
the most part, only defense contractors and academic institutions
could gain access to what was then known as the ARPAnet (Advanced
Research Projects Agency network of the Department of Defense).
With the advent of high-speed modems for digital communication over
common phone lines, some individuals and organizations not directly
tied to the main digital pipelines began connecting and taking
advantage of the network's advanced and global communications.
Nonetheless, it wasn't until these last few years (around 1993,
actually) that the Internet really took off.
Several crucial events led to the meteoric rise in popularity of the
Internet. First, in the early 1990s, businesses and individuals eager
to take advantage of the ease and power of global digital
communications finally pressured the largest computer networks on the
mostly U.S. government-funded Internet to open their systems for
nearly unrestricted traffic. (Remember, the network wasn't
designed to route information based on content -- meaning that
commercial messages went through university computers that at the
time forbade such activity.)
True to their academic traditions of free exchange and sharing, many
of the original Internet members continued to make substantial
portions of their electronic collections of documents and software
available to the newcomers -- free for the taking! Global
communications, a wealth of free software and information: who could
resist?
Well, frankly, the Internet was a tough row to hoe back then. Getting
connected and using the various software tools, if they were even
available for their computers, presented an insurmountable technology
barrier for most people. And most available information was
plain-vanilla ASCII about academic subjects, not the neatly packaged
fare that attracts users to online services such as America Online,
Prodigy, or CompuServe. The Internet was just too disorganized, and,
outside of the government and academia, few people had the knowledge
or interest to learn how to use the arcane software or the time to
spend rummaging through documents looking for ones of interest.
1.1.2. HTML and the World Wide Web
It took another spark to light the Internet
rocket. At about the same time the Internet opened up for business,
some physicists at CERN, the European Particle Physics Laboratory,
released an authoring language and distribution system they developed
for creating and sharing multimedia-enabled, integrated electronic
documents over the Internet. And so was born Hypertext
Markup Language (HTML), browser software, and the World
Wide Web. No longer did authors have to distribute their work as
fragmented collections of pictures, sounds, and text. HTML unified
those elements. Moreover, the World Wide Web's systems enabled
hypertext
linking, whereby documents automatically reference other
documents, located anywhere around the world: less rummaging, more
productive time online.
Lift-off happened when some bright students
and faculty at the National Center for Supercomputing Applications
(NCSA) at the University of Illinois, Urbana-Champaign wrote a web
browser called Mosaic. Although designed primarily for viewing HTML
documents, the software also had built-in tools to access the much
more prolific resources on the Internet, such as FTP archives of
software and Gopher-organized collections of documents.
With versions based on easy-to-use graphical-user interfaces familiar
to most computer owners, Mosaic became an instant success. It, like
most Internet software, was available on the Net for free. Millions
of users snatched up a copy and began surfing the Internet for
"cool web pages."
1.1.3. Golden Threads
There you have the history of the Internet and the World Wide Web in
a nutshell: from rags to riches in just a few short years. The
Internet has spawned an entirely new medium for worldwide information
exchange and commerce, and its pioneers are profiting well. For
instance, when the marketers caught on to the fact that they could
cheaply produce and deliver eye-catching, wow-and-whizbang
commercials and product catalogs to those millions of web surfers
around the world, there was no stopping the stampede of blue suede
shoes. Even the key developers of Mosaic and related web server
technologies sensed potential riches. They left NCSA and formed
Netscape Communications to produce
commercial web browser and server
software.
Business users and marketing opportunities have helped invigorate the
Internet and fuel its phenomenal growth, particularly on the World
Wide Web. But do not forget that the Internet is first and foremost a
place for social interaction and information sharing, not a strip
mall or direct advertising medium. Internet users, particularly the
old-timers, adhere to commonly held, but not formally codified, rules
of netiquette that prohibit such things as
"spamming" special-interest newsgroups with messages
unrelated to the topic at hand or sending unsolicited email. And
there are millions of users ready to remind you of those rules should
you inadvertently or intentionally ignore them.
Certainly, the power of HTML and network distribution of information
go well beyond marketing and monetary rewards: serious informational
pursuits also benefit. Publications, complete with images and other
media like executable software, can get to their intended audience in
a blink of an eye, instead of the months traditionally required for
printing and mail delivery. Education takes a great leap forward when
students gain access to the great libraries of the world. And at
times of leisure, the interactive capabilities of HTML links can
reinvigorate our otherwise television-numbed minds.
 |  |  | | 0.6. Acknowledgments |  | 1.2. Talking the Internet Talk |
Copyright © 2002 O'Reilly & Associates. All rights reserved.
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