1966... I knew nothing about computers, but I knew there
had to be a better way to produce documents than dictating
them, reviewing a draft, marking up the draft with corrections,
reviewing the retyped draft, and then, in frustration,
seeing that the typist had introduced more errors while
making the corrections...
- Charles Goldfarb, The
Roots of SGML -- A Personal Recollection, 1996.
HTML is the simple and powerful language
used to describe web pages, and is still used as the main interface
language to the web.
In 1969, the same year the ARPANET was
Goldfarb, Edward Mosher, and Raymond Loriewas invented the
Generalized Markup Language (GML) to facilitate text management
in large information systems. GML was based on the work of Rice
and Tunnicliffe with
tagging schemes, and added a formal document structure, so that
any computer program could automatically process and format the
individual parts of the document.
In 1980, the American National Standards Institute (ANSI) committee
built on GML and published a working draft of Standard GML, or
SGML. Major adopters of the standard included the US Internal Revenue
Service and Department of Defense. A draft international standard
was adopted by the European Community in 1985, and a final standard
was published as ISO 8879:1986. The final standard was published
with a working SGML system developed by Anders Berglund, then of
the European Particle Physics Laboratory (CERN).
A few years later another scientist at CERN, Tim
Berners-Lee, invented the HyperText Markup Language
(HTML) to define the structure of web pages. Tim never planned
HTML to be more than a structure into which a wide range of
multi-media documents would be fitted, but it was designed
well enough that it came to be used to present a wide range
of content itself. The main structure of modern HTML was agreed
at a meeting at the first WWW Conference held the week of 25
May, 1994, including the incorporation of tables, graphics,
and mathematics symbols, as would be expected for a language
then aimed at academic work.
HTML is designed to be as simple as possible. Each command consists
of an opening tag in angle brackets, like <tag>, and a closing
tag with an added slash, like </tag>. Some of the most common
commands are listed below, together with the result displayed when
the HTML is read by a web browser.
water is <b>very</b> blue.
water is very blue.
wind is <i>very</i> warm.
wind is very warm.
a small world
a small world
main page is
main page is here.
Every web page is written in HTML, which is text based, so it's
easily and quickly communicated across the Internet. On most browsers
you can view the HTML for any web page you visit, including this
one, by selecting "View Source" from the browser toolbar, or from
a pop-up menu appearing when you right-click on a particular frame.
When you are finished viewing the web page source you can close
that window without affecting any of the pages you are viewing.
Dan Connolly, Jon Bosak, and others at the W3C have also developed
a successor to SGML called the Extensible Markup Language (XML),
which provides the structure to enable design of a range of languages
like HTML for various purposes, and is in wide and increasing use.
Berners-Lee published a specification for HTML in RFC
1866, Hypertext Markup Language - 2.0, November 1995.
Generated HTML. There are several technologies used to
dynamically create web pages on the fly whenever they are requested
by a visitor, often by some variation on reading values from a
database, for example to provide current weather or sports information.
These methods often give their pages a different three-letter extension
than ".htm", although the page as it is transmitted over
the Internet and received by your browser is still constructed
in HTML so your browser can read it. Three leading technologies
for web page generation are listed below:
- .asp --
Active server pages (ASP)
- .cgi --
Common gateway interface (CGI)
- .php --
These automated methods can produce powerfully interactive content,
but have a key disadvantage: the data does not exist independently,
it depends on the operation of a program which is much more complicated
than data and can have many of its own dependencies. If the program
fails to work perfectly, you often get no data or wrong data --
perhaps all the temperatures are set to zero and every sports team
is tied. A real example from 7 May 2003 can be found below -- this
message was returned instead of the expected forum web
searchengineforums.com: The Search Engines: Google:
Google Quick Start
There seems to have been a slight problem with the database. Please try again by pressing the refresh button in your browser.
error in Invalid SQL: SELECT thread FROM forum_stats WHERE forum='Forum28'
AND last_post < ORDER BY last_post DESC LIMIT 1
mysql error: You have an error in your SQL syntax near 'ORDER BY last_post DESC LIMIT 1' at line 1
mysql error number: 1064
Date: Wednesday 07th of May 2003 05:32:11 PM
Resources. The following sites provide additional information