Page 106 - Electronic Commerce

Technology Infrastructure: The Internet and the World Wide Web

the Association of American Publishers, Hewlett-Packard, and Kodak, use SGML because
they have complex document-management requirements.
SGML is nonproprietary and platform independent and offers user-defined tags. 81
However, it is not well suited to certain tasks, such as the rapid development of Web
pages. SGML is costly to set up and maintain, requires the use of expensive software tools,
and is hard to learn. Creating document-type definitions in SGML can be expensive and
time consuming.

Hypertext Markup Language
HTML includes tags that define the format and style of text elements in an electronic
document. HTML also has tags that can create relationships among text elements within
one document or among several documents. The text elements that are related to each
other are called hypertext elements.
HTML is easier to learn and use than SGML. HTML is the prevalent markup language
used to create documents on the Web today. The early versions of HTML let Web page
designers create text-based electronic documents with headings, title bar titles, bullets,
lines, and ordered lists. As the use of HTML and the Web itself grew, HTML creator
Berners-Lee turned over the job of maintaining versions of HTML to the W3C. Later
versions of HTML included tags for tables, frames, and other features that helped Web
designers create more complex page layouts. The W3C maintains detailed information
about HTML versions and related topics on its W3C HTML Working Group page.
The process for approval of new HTML features takes a long time, so Web browser
software developers created some features, called HTML extensions, that would only work
in their browsers. At various times during the history of HTML, both Microsoft and
Netscape enabled their Web browsers to use these HTML extension tags before those tags
were approved by the W3C. In some cases, these tags were enabled in one browser and
not the other. In other cases, the tags used were never approved by the W3C or were
approved in a different form than the one implemented in the Web browser software. Web
page designers who wanted to use the latest available tags were often frustrated by this
inconsistency. Many of these Web designers had to create separate sets of Web pages for
the different types of browsers, which was inefficient and expensive. Most of these tag
difference issues were resolved when the W3C issued the specification for HTML
version 4.0 in 1997, although enough of them remained to cause regular problems for Web
designers.
After HTML 4.0 was finalized in 1999, development on new versions of HTML
slowed. Browser developers worked on adding new features to their software and the
W3C directed its efforts to other matters. In 2007, three browser developers (Apple,
Opera, and the Mozilla Foundation) began working on an updated version of HTML that
would include features such as audio and video within the markup language itself. Audio
and video elements in Web pages have always required the use of add-on software. The
current working draft of HTML version 5.0 will become finalized in July 2014, but its
feature set was frozen in May 2011 and most Web browsers already are compatible with
this latest version. You can learn more about this latest HTML version by visiting the
W3C HTML 5 page.

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