Matakuliah : M0284/Teknologi & Infrastruktur E-Business Tahun : 2005
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Matakuliah Tahun Versi : M0284/Teknologi & Infrastruktur E-Business : 2005 : <<versi/revisi>> Pertemuan 17 Programming Languages for E-Business/E-commerce 1 Learning Objectives • Differentiate between HTML and XML and appreciate the role of XML in e-business • Create an XML document that uses a simple cascade style sheet and displays its content in an IE browser • Learn how to use an external document type definition (DTD) file to specify the document structure required for an XML document • Write an extensible style sheet (XSL) to specify the formatting requirements of a document and appreciate how its programming features are used 2 Chapter Overview • • • • Languages used on the WWW Similarities and dissimilarities Advantages and disadvantages Understanding the newer technologies in the offing 3 Aspects of content delivery • Languages for formatting and aesthetics (HTML, DHTML, Style Sheets) • Structure and semantics of the content (XML) • Scripting languages for processing of data and interface with external applications (CGI, Java Server Pages, JavaScript, VBScript, Coldfusion, PHP) 4 History of Web • Originally availability and dissemination of information • SGML – Standard Generalized Markup Language • Had mark-up language, with hyper links, no complex features • HTML- HyperText Markup Language • DHTML – Dynamic HTML, more flexible • Not standardized, no common standards 5 adopted by the leading browsers. XML – eXtensible Markup Language • Supported by major players like Microsoft and IBM. • Projected to be the most relevant web standard of the future. • Best suited for E-Commerce (as front-end and back end sub-systems can be conveniently integrated). 6 PDF – Portable Document File • Proprietary format from Adobe • Best suited for distributing complex documents • Preservation of original style, format etc. • Freely available Reader (Adobe Reader), – no charge for viewing the documents. 7 SGML – Standard Generalized Markup Language • Born out of generic coding and mark-up languages in early 1970’s. • SGML as a formal standard under ISO • First edition in 1986 • Amended in 1988. 8 SGML (contd.) • Specifies a standard method for describing the structure of a document. • Open-ended definitions • Does not directly specify any type of content data, no restrictions on any type of data. • Flexible, able to describe any logically structured set of information (e.g. form, memo, book, dictionary, spreadsheets, databases). • Sophisticated, used by a loyal group of developers, 9 SGML - Not a markup scheme. • But a means for describing any markup scheme. • SGML can be used for developing markup schemes for different document classes. 10 Uses of SGML • Publishing • Multi-media • Save and store information for long term (e.g. AAP, ATA, CALS etc.) 11 HTML – Hyper Text Markup Language • Most prevalent form of web pages is HTML. • Born out of SGML’s rejection, is easy to use. • Both Microsoft I.E. and Netscape Communicator support it. • HTML content can be formatted with the addition of a few tags. • Can be created using dynamic code generators or templates • Word processor files, even MS-Excel, Access and PowerPoint files can be exported to HTML. 12 Advantages and disadvantages of HTML • HTML has pre-defined tags, both a strength and a weakness, depending on the user’s experience. • Elements of HTML include title, body, background, paragraphs, lists, tables, forms, formatting (bold, italics, underline) • Can add Java applets and ActiveX controls within HTML pages. • HTML can be developed using editors ranging in complexity from MS Notepad to WYSIWYG. • Limitation – tags cannot be created for new undefined structure, format. 13 Insertion of pictures and graphics in HTML • One of the main reasons for the success of the WWW. • Inline images, hyper-linked images (stored on a different page). • Types of raster graphics: GIF, JPEG, PNG, no need for plug-ins. 14 Syntax for inserting a picture <html> <head> <title> Picture of a dog </title> </head> <body> <IMG SRC = “dog.jpg” border = 0> </body> </html> 15 Other features • Align – takes values bottom, top, left, middle and right. • Alt- an alternative message • Border – defines border width • Height- height of the image and allows resizing • HSpace- horizontal space • SRC- URL of the image • VSpace- vertical space • Width – width of the image and allows resizing 16 Most common HTML tags <html> </html> Marks the beginning of the document and end <head> </head> Specifies the beginning and end of header <title> </title> Indicate the title ; not displayed on web page <body> </body> Indicates the main part of web page <hn> Specifies the size of heading from 1 (large) to 6 </hn> <p> </p> Delimits a paragraph with a blank line <li> </li> Delimits the beginning and end of unordered list <hr> Inserts a horizontal line <br> Indicates a cut in the flow going to next line <b> </b> Indicates that the text within is emphasized <i> </i> Indicates that the text within is italicized <u> </u> Indicates that the text is underlined <table> </table> Inserts a table in the document <form> </form> Inserts a form in the document 17 Background color <body bgcolor = “#99CCFF”> Here, 99 denotes red, CC denotes green and FF denotes blue in hexadecimal notation. or <body background = “lightgreen.jpg”> 18 For additional functionalities, we might want to add Java applets <APPLET CODEBASE=“..” CODE=“hm30.class” NAME=“HotMedia” WIDTH=“239” HEIGHT=“50”> <PARAM NAME=“mvrfile” VALUE=“data/preview.mvr”> </APPLET> 19 Links to other pages • Hyper-links- most attractive feature in Hypertext media. • Makes navigation through the pages very convenient. • Useful for e-commerce also, as it can be used to balance and distribute the load among various servers. Delegate time consuming operations to the service providers. • <A HREF=“second.htm”> second page </A> • Here <A> and </A> act as anchors for the link. HREF indicates the URL of the target page. 20 Web publishing • A web server should be running on the computer where the document to be published is located. • FTP (File Transfer Protocol) allows remote insertion of pages on a web server. 21
