Introduction to the World Wide Web

GRC 175 Class Lessons

Introduction to the World Wide Web

LECTURE 1 Brief History of the WWW • Client-Server Model

WWW & the Internet

The World Wide Web is just one of the services available through the Internet.

Like other Internet services, the World Wide Web is not a network. Instead, it is a way of organizing information so that any computer around the world that operates according to certain rules can access it.

The rules that specify how to access and transfer files over the web is called HTTP (Hypertext Transfer Protocol).

The researcher who is mainly responsible for creating the World Wide Web, Tim Berners-Lee, developed a system for linking information which comprised three critical elements:

a way of giving everything a uniform address
a protocol for transmitting these linked bits of information
a language for encoding the information.

Since a basic document format was required for passing information back and forth between computer systems, Berners-Lee developed HTML (HyperText Markup Language) based on an existing language, SGML (Standard Generalized Markup Language).

The following are the major characteristics embodied in HTML:

Simplicity—Keenly aware of the incredible complexity inherent in SGML, Berners-Lee opted for a tiny subset of tags for describing a document and did not bother with a method for describing a document's styles. Part of the incredible growth of the web has been attributed to its simplicity, which led to the ease of creating documents for reading in browsers

Universality—HTML and its derivatives can be read on virtually any computer and on many devices like phones and hand-held units.

Degradability—While maintaining a simple system, as well as one that worked across the diversity of the Internet, Berners-Lee realized that HTML would eventually have to expand.

To accommodate managed growth, he added a final axiom regarding new versions: they must never break older releases of the language.

So as the World Wide Web evolved, it would never require upgrades. New versions would simply be embellishments of old versions.

Any browser running on any computer system could interpret this basic collection of tags and interpret them in the same way. High-end workstations could present typographically rich documents on color monitors while simple terminal emulators could offer a stripped down version that matched the limited capacity of the device. Suddenly, everyone could exchange electronic documents in an incredibly simple way.