Sheet 1XML Technology in E-Commerce 2001Lecture 1 XML Technology in E-Commerce Lecture 1 WWW, HTML, CSS, XML, Meta-modeling

Sheet 2XML Technology in E-Commerce 2001Lecture 1 Lecture Outline World Wide Web - facts, architecture; HTML; CSS; XML –Markups; –Well-formedness; –Meta-modeling;

Sheet 3XML Technology in E-Commerce 2001Lecture 1 WWW –Global hypertext project at CERN; –Proposed by Tim Berners-Lee in 1989; Web Consortium (W3C) - –Founded in 1994; –Three hosts - MIT, INRIA, Keio University; –Leads the evolution of the Web; –More than 20 web-related specifications; World Wide Web

Sheet 4XML Technology in E-Commerce 2001Lecture 1 World Wide Web Architecture Web Server Web Browser HTTP request for Web Resource HTTP response - usually a Web page HTTP - Hypertext Transport Protocol; HTML - Hypertext Markup Language; URI - Uniform Resource Identifier - a naming scheme for resources on the Web;

Sheet 5XML Technology in E-Commerce 2001Lecture 1 HTML Example XML Technology in E-Commerce Lecture 1 Example of HTML Resources: W3C Web Consortium Other Examples - Deitel 2.4, page 26; 3.2, page 47

Sheet 6XML Technology in E-Commerce 2001Lecture 1 Enable development of web applications - user interface is presented by the browser; Web server handles form data through server extensions; Opens a possibility for dynamic web pages; CGI (Common Gateway Interface) - protocol for data exchange between the server and its extensions (CGI scripts); Popular languages for CGI programming - Perl, C, Python, Java, VBScript, JavaScript; HTML Forms Examples - Deitel 3.4, page 52

Sheet 7XML Technology in E-Commerce 2001Lecture 1 HTML Links Web page Web Resource Link has two ends (anchors) and direction; A element - sets up an anchor: – Java Home sets up a source anchor. href attribute contains an URI; – TOC - sets up a destination anchor; Link behavior - destination resource is retrieved and displayed;

Sheet 8XML Technology in E-Commerce 2001Lecture 1 Meta data about the document: HTTP response headers: Data for search agents: HTML tags usage

Sheet 9XML Technology in E-Commerce 2001Lecture 1 Multimedia content - plug-in and ActiveX technology; Scripts - dynamic and interactive web pages on the client side; Java Applets - programs executed in the browser environment; HTML editors - FrontPage, Dreamweaver, NetObjects Fusion, Adobe GoLive; Demo: Editing web pages with FrontPage HTML Multimedia, extra functionality, editors

Sheet 10XML Technology in E-Commerce 2001Lecture 1 CSS Cascading Style Sheets Purpose - specify the layout of web pages; Benefits: –Separate structure from presentation; –Impose consistent look and feel to the entire site; –Promotes reusability; Specifications: –CSS level 1 and 2; –CSS level 3 - work in progress;

Sheet 11XML Technology in E-Commerce 2001Lecture 1 Inline styles some text style element p {font-size : 20pt; color : blue;} External style sheets CSS Declaration

Sheet 12XML Technology in E-Commerce 2001Lecture 1 Style origin: –User agent (browser) default style sheet; –User style; –Author style; Cascading order - how to resolve conflicts between style rules; Inheritance - an element inherits style properties from its ancestors; CSS Cascading and Inheritance More info - Deitel 4.4, page 84

Sheet 13XML Technology in E-Commerce 2001Lecture 1 XML XML, HTML, SGML HTML Drawbacks: Fixed Tags Set Poor Linking Does not support validation Simple structures Specifies only presentation Relations between SGML, HTML and XML:

Sheet 14XML Technology in E-Commerce 2001Lecture 1 XML Idea Sherlock Holmes Baker Street 221b London England

Sheet 15XML Technology in E-Commerce 2001Lecture 1 XML Basic terms Annotated XML Specification:

Sheet 16XML Technology in E-Commerce 2001Lecture 1 Characters in the XML document form markups and character data; Markups: –start, end and empty element tags; –entity and character references; –comments; –CDATA delimiters; –Document type declarations; –Processing Instructions; All other characters form character data; XML Characters and Markups

Sheet 17XML Technology in E-Commerce 2001Lecture 1 ……..Content……….. XML Elements and element’s content Start tag End tag Element’s content Element’s content: Only elements; Empty; Mixed (character data and other elements); - Empty element Attribute specification

Sheet 18XML Technology in E-Commerce 2001Lecture 1 Sherlock Holmes Baker Street 221b 1111 London England Sherlock Holmes and Doctor Watson lived at 221b Baker Street between , according to the stories written by Sir Arthur Conan Doyle. XML Example

Sheet 19XML Technology in E-Commerce 2001Lecture 1 Processing Instructions: CDATA Sections: Hello World! ]]> <![CDATA[ if((x==0) && (y <2)) System.out.println(“Ok!”); ]]> XML Processing Instructions and CDATA Sections

Sheet 20XML Technology in E-Commerce 2001Lecture 1 Purpose - resolve name collisions in a single XML document; Definition - Set of names uniquely identified by URI, used for element types and attribute names; Namespace declaration: ………. XML Namespaces Examples - Deitel 5.8, page 123

Sheet 21XML Technology in E-Commerce 2001Lecture 1 XML Meta-modelling - well-formedness EBNF Pascal Grammar a Pascal Program Defines EBNF XML GrammarWF Constraints an XML Document Defines

Sheet 22XML Technology in E-Commerce 2001Lecture 1 XML Meta-modelling - validity

Sheet 23XML Technology in E-Commerce 2001Lecture 1 Browser support: –Netscape - XML, CSS1, CSS2 (partly); –IE 5 - XML, CSS1, CSS2 (partly), XSLT; –Opera - XML, CSS1, CSS2(partly); XML Editors: –XML Spy 3.5; –XMetal; –Epic; –FrameMaker; Demo: Visualizing XML files in IE5, editing with XML Spy XML Tool Support

Sheet 24XML Technology in E-Commerce 2001Lecture 1 Summary Today’s Web - HTTP, URI, HTML, CSS; XML is a technology for creating markup languages; XML documents contain character data and markups; Elements are the main building blocks for the document structure; Document well-formedness means conformance to the XML grammar and constraints; Read: Deitel 1..5, Well-formedness and Validity of XML Documents Skip: Deitel 3.3, 3.5, 3.7, 3.9, 3.10, ; Assignment: Deitel Ex 5.4 and Ex 5.7, pages 132, 133