1、Web Sites Design and ProgrammingLecturer: Lijie Guo Room: XNA508Phone: 23678517Email: guo_* 1-1 School of Computer Science and TechnologyIntroduction to XHTMLWDP CN 第二章 ,第三章 , 22 83WDP EN Chapter 2 , Chapter 3 , 31 105P3W CN 第 二 章 , 22 68Date 2 School of Computer Science and TechnologyOverviewpOrigi
2、ns and evolution of HTML and XHTMLpBasic SyntaxpStandard document structurepBasic text markuppImagespHypertext linkspListspTablespFormspFramesDate 3 School of Computer Science and TechnologyMarkup Languagesp Procedural markupl focused on the presentation of textl usually visible to the user editing
3、the text filel interpreted by software in the order in which it appears, like a procedural languagep Descriptive (semantic) markupl focus on the structural aspects of a document (e.g. being able to parse it and build a structure in memory)l leave the visual presentation of the structure to the inter
4、preter Date 4 School of Computer Science and TechnologySGMLpSGML stands for “Standard Generalized Markup Language“.pSGML is a method for creating interchangeable, structured documents.pYou can do the following:l assemble a single document from many sources (such as SGML fragments, word processor fil
5、es, database queries, graphics, video clips, and real-time data from sensing instruments);l define a document structure using a special grammar called a Document Type Definition (DTD);l add markup to show the structural units in a document.Date 5 School of Computer Science and TechnologySGML (cont.)
6、pThe official definition of SGML is in the international standard ISO 8879:1986 “Information Processing -Text and Office Systems -Standard Generalized Markup Language (SGML)“.pSGML is non-proprietary. Publication and amendments to the International Standard are controlled solely by the ISO. Date 6 S
7、chool of Computer Science and TechnologyHow Is SGML Used?pSGML enables the description of structured information independent of how that information is processed.pIt is a meta-language that provides a standard syntax for defining descriptions of classes of structured information; these descriptions
8、are called document type definitions (DTDs).Date 7 School of Computer Science and TechnologyHow Is SGML Used? (cont.)pInformation can be “marked up“ (or chunked and classified) according to a DTD, so that its structure is made explicit and accessible to parsers.pThe “markup“ can be checked against a
9、 DTD to ensure that it is valid, and thus that the structure of the information conforms to that of the class described by the DTD.Date 8 School of Computer Science and TechnologySGML and HTMLpHTML is an SGML application (a DTD and a set of processing conventions).pHTML browsers do not support many
10、basic SGML constructions, like arbitrary entities, but nearly all SGML authoring tools are capable of producing good HTML documents. Date 9 School of Computer Science and TechnologySGML and XMLpUnlike HTML, XML is not an SGML application.pXML is a meta-language like SGML, allowing users to create an
11、y tags needed (hence “extensible“) and then describing those tags and their permitted uses.pXML was developed by the World Wide Web Consortium to simplify SGML by focusing on a particular problem documents on the Internet.pXML is the most famous “descendant”of SGML. (Why? Its simplification of SGML makes a great but complex idea manageable.)Date 10 School of Computer Science and Technology
