Web Technologies

Web TechnologiesAnupriya Sharma

Table of Content

• HTML

• XHTML

• XML

HTML

• What is HTML

• History

• What is it used for

• Tags & Structure Sample

• Conclusion

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

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

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.

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 …

HTML Standard Tags• TAG: A command inserted in a document that specifies how

the document, or a portion of the document, should be formatted. Tags are used by all format specifications that store documents as text files. This includes SGML and HTML.

• Attribute refers to the properties of the HTML elements• TAG is, which stands within "<...>"• to an opening TAG belongs usually a closing TAG (< font>...

</font>) • Comment tags: • There are special tags who not need an end tag, like <br>

HTML Basic Structure<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"

"http://www.w3.org/TR/html4/loose.dtd"><html><head><title>Title of the page</title></head><body><h1><i>HTML</i> - the language of the

web</h1> </body></html>

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

XHTML

• What is XHTML

• History

• Main characteristics of XHTML

• Syntax rules

• Conclusion

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

History

• Introduced in 26 January 2000 by W3C as the new official standard

• Reason: Problems because of "bad" and "unsuitable" HTML => for search "more cleanly" and "more uniformly" programming

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

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.

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

=> More expenditure of time

XML

• What is XML

• XML – Motivation

• XML – Classification

• Sample

• Conclution

What is XML

• XML (EXtensible Markup Language)

• Guidance for writing of „Document Type Definitions“ DTD‘s

• XML is more general and uniform than HTML, and simpler than SGML

• SGML - (arcane features) + (new acronym) = XML!

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

XML - Classification

Structured DataSemi

Structured DataNon

Structured Data

RATIONALDATA BASES

XML FLOW TEXT

Sample Code

<?xml version=„1.0“ encoding=„ISO-8859-1“ ?> <book isbn=„3423085169“> <titel>Sofies Welt</titel> <autor> <name>Gaarder</name> <firstname>Jostein</firstname> </autor> <publisher>DTV</ publisher> <year>1993</year> </book>

End - Conclusion

• HTML– Markup language for the Web– Version and compatibility problems

• XHTML– Tryes to solve this problems

• XML– machine-machine communication

Thanks for your attention!

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