Web Technologies

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Web Technologies

• By Andreas Vetter and Yong Soo Deutschle

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Table of Content

• HTML
• XHTML
• XML

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HTML

• What is HTML
• History
• What is it used for
• Tags Structure Sample
• Conclusion

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What is HTML

• HTML (HyperText Markup Language)
• Language for publications in the World Wide Web,
  text format for HTTP
• Basic language English
• Developed 1990 by Berners Lee
• based very strongly on SGML

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SGML a Brief Introduction

• Standardized General Markup Language
• In 1986, ISO approved an international standard
  for descriptive markup
• SGML is a metalanguage for defining markup
  languages
• HTML is one example of an SGML-defined language

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History of HTML

• HTML 2.0 is the official standard, which defines
  those basic functions of HTML, which are
  meaningfully represented by all Web Browsern.
• HTML 3.2 is the most common used standard, which
  covers those HTML elements, which are supported
  to a large extent by nearly all Browser versions
  (starting from 1996/97).
• HTML 4.0 is a suggestion of the W3-Consortium,
  which is at least partly supported by newer
  Browser versions (starting from 1997/98).
• The advancement of HTML starting from 1999/2000
  will go into the direction from XHTML.

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What is it used for

• Presenting information in LAN / WAN
• Structure your text-based information
• Hyperlinks to reach following texts
• To Put images on your docs
• Basic structure for all web applications, like
  Guestbooks, Online Stores, Forums, etc

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HTML Standard Tags

• TAG is, which stands within "lt...gt"
• to an opening TAG belongs usually a closing TAG
  (lt fontgt... lt/fontgt)
• Comment tags lt!-- .... --gt
• There are special tags who not need an end tag,
  like ltbrgt

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HTML Basic Structure

• lt!DOCTYPE HTML PUBLIC
• "-//W3C//DTD HTML 4.01 Transitional//EN"
  "http//www.w3.org/TR/html4/loose.dtd"gt
• lthtmlgt
• ltheadgt
• lttitlegtTitle of the pagelt/titlegt
• lt/headgt
• ltbodygt
• lth1gtltigtHTMLlt/igt - the language of the weblt/h1gt  
• lt/bodygt
• lt/htmlgt

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Conclusion

• Advantage HTML is easy to learn
• Problems
• Almost nobody really cares about the standards
  of w3c, because the Microsoft Internet Explorer
  (Leading Browser) is very obliging
• As a result the parsers of the non-microsoft
  browsers can have significant problems in
  displaying pages correctly

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XHTML

• What is XHTML
• History
• Main characteristics of XHTML
• Syntax rules
• Conclusion

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What is XHTML

• EXtensible HyperText Markup Language
• Supposed to replace HTML
• nearly identically to HTML 4.01
• stricter and "more cleanly" version of HTML
• HTML 4.01 on XML-Base

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History

• Introduced in 26 January 2000 by W3C as the new
  official standard
• Reason Problems because of "bad" and
  "unsuitable" HTML gt for search "more cleanly"
  and "more uniformly" programming

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Main characteristics of XHTML

• correct nesting of the tags
• XHTML documents must keep a certain form
• permit no capital letters for the tags
• All elements must be closed END tag necessarily

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Important syntax rules

• Attribute names must be written in small letters
• Attributes must stand in " "
• No attributes shortening
• The ID attribute replaces the name attribute
• The XHTML DTD defines obligatory elements.

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Conclusion

• XHTML is supposed to make the HTML-Jungle clean,
  to make the Web-Pages suitable for all browser
  types.
• Disadvantages
• Web developers have to obey the rules
• Errors will not be tolerated
• gt More expenditure of time

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XML

• What is XML
• XML Motivation
• XML Classification
• Sample
• Conclution

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What is XML

• XML (EXtensible Markup Language)
• Guidance for writing of Document Type
  Definitions ? DTDs
• XML is more general and uniform than HTML, and
  simpler than SGML
• SGML - (arcane features) (new acronym) XML!

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XML - Motivation

• For closing gaps between machine-machine
  communication ...
• ... applicable in the WWW
• Easy to create
• For humans and machines readable
• To cover as much as possible areas of application
  

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XML - Classification
Structured Data
Semi Structured Data
Non Structured Data
FLOW TEXT
XML
RATIONAL DATA BASES
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Sample Code

• lt?xml version1.0 encodingISO-8859-1 ?gt
• ltbook isbn3423085169gt
• lttitelgtSofies Weltlt/titelgt
• ltautorgt
• ltnamegtGaarderlt/namegt
• ltfirstnamegtJosteinlt/firstnamegt
• lt/autorgt
• ltpublishergtDTVlt/ publishergt
• ltyeargt1993lt/yeargt
• lt/bookgt

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End - Conclusion

• HTML
• Markup language for the Web
• Version and compatibility problems
• XHTML
• Tryes to solve this problems
• XML
• machine-machine communication

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Thanks for your attention!

• Questions?