1. April 20023CSG11 Electronic Commerce Markup languages John Wordsworth Department of Computer Science The University of Reading J.B.Wordsworth@rdg.ac.uk Room 129, Ext 6544

2. April 20023CSG12 Lecture objectives Explain what is meant by markup, and observe how markup has been standardised. Describe the notion of a document type. Distinguish SGML applications and profiles. Outline the rules of XML. Read a simple DTD. Describe some XML applications.

3. April 20023CSG13 What is markup Written instructions to the printer Hidden codes stored within the text of a document in a word processor Explicit tags to define a document’s structure (Generalised Markup Language) Standard Generalised Markup Language (ISO 8879): rules for defining markup for different types of documents (DTDs)

4. April 20023CSG14 A document structure LectureCourse FrontMatter TitlePage, Title, Author, Date, Copyright Preface, TOC Body Outline, SampleExamination, Timetable, Lecture+ Title, Lecturer, Objectives, Slide+, Image, Notes Supplementary, SAQs BackMatter Glossary, ResourceList, Index

5. April 20023CSG15 SGML profiles and applications SGML profilesapplications XML HTML applications WMLmathMLXSL

6. April 20023CSG16 A bit of a sample DTD

7. April 20023CSG17 A bit of a sample document Electronic Commerce 30 April 2001 John Wordsworth 2001 This document defines the course 3/CS/G1, module CS607

8. April 20023CSG18 More of the sample document Introduction John Wordsworth To explain how the course works... These are the notes See also...

9. April 20023CSG19 Some rules about XML documents 1.Every element has an opening tag and an end tag, or is empty. 2.There is a single outermost element that encloses the whole of the document. 3.Every element that is not the outermost element is entirely contained in the content of some element. If a document obeys these rules it is well-formed. If its structure agrees with a DTD, the document is valid with respect to the DTD.

10. April 20023CSG110 Some XML applications WML – Wireless Markup Language Used to define content to be displayed on mobile phones. Deck, Card, Links (internal, external), input fields XSL – Extensible Stylesheet Language Used to define stylesheets, which contain rules for transforming XML documents into other textual formats (XML for example)

11. April 20023CSG111 Messages for a banking application...

12. April 20023CSG112 Key points Markup has progressed from being customised instructions to printers to an essential element of electronic commerce. The key to understanding a document’s structure is its DTD. SGML defines rules for constructing DTDs. HTML is an SGML application – a DTD constructed according to the SGML rules. XML is an SGML profile, a more restrictive set of rules. XML applications are widely used in e-commerce, and elsewhere.