Datasheet

❑ Information about the document being delivered (date modified, size, encoding, and so on)

Last-Modified: Sat, 26 Oct 2002 09:12:14 GMT

ETag: “19b498-100e-3dba5c6e”

Accept-Ranges: bytes

Content-Length: 4110

Keep-Alive: timeout=15, max=100

Connection: Keep-Alive

Content-Type: text/html; charset=iso-8859-1

❑ The content of the document itself (in this case, the default Debian/GNU Linux Apache wel-

come page)

<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 3.2//EN”>

<HTML>

<HEAD>

. . .

A few seconds after the full document is delivered, the server closes the connection.

Connection closed by foreign host.

This dialog is HTTP at its simplest, but it does a good job of illustrating how the protocol works.

Hypertext Markup Language

Hypertext Markup Language (HTML) was devised as an easy means to format textual documents. HTTP

is the method for delivering HTML documents, which the client browser then renders into an on-screen

image. This section covers the development and evolution of HTML.

In the Beginning — HTML

HTML and HTTP were both invented by Tim Berners-Lee, who was then working as a computer and

networking specialist at a Swiss research institute. He wanted to give the institute’s researchers a simple

markup language that would enable them to share their research papers via the Internet. Berners-Lee

based HTML on Standard Generalized Markup Language (SGML), an international standard for marking

up text for presentation on a variety of physical devices. The basic idea of SGML is that the document’s

structure should be separated from its presentation.

To date, HTML has gone through four major standards, including the latest, 4.01. In addition to HTML,

Cascading Style Sheets (CSS) and Extensible Markup Language (XML) have also provided valuable con-

tributions to the way of the Web.

Most of the standards used on the Web are developed and/or ratified by the World Wide Web Consortium

(W3C). The resulting specifications can be found online at the W3C Web site,

www.w3c.org.

The Basics of HTML

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