Introduction to XMLExtensible Markup Language课件.pptVIP

Introduction to XMLExtensible Markup Language Carol Wolf Computer Science Department 精品文档 What is XML XML stands for eXtensible Markup Language. A markup language is used to provide information about a document. Tags are added to the document to provide the extra information. HTML tags tell a browser how to display the document. XML tags give a reader some idea what some of the data means. 精品文档 What is XML Used For? XML documents are used to transfer data from one place to another often over the Internet. XML subsets are designed for particular applications. One is RSS (Rich Site Summary or Really Simple Syndication ). It is used to send breaking news bulletins from one web site to another. A number of fields have their own subsets. These include chemistry, mathematics, and books publishing. Most of these subsets are registered with the W3Consortium and are available for anyone’s use. 精品文档 Advantages of XML XML is text (Unicode) based. Takes up less space. Can be transmitted efficiently. One XML document can be displayed differently in different media. Html, video, CD, DVD, You only have to change the XML document in order to change all the rest. XML documents can be modularized. Parts can be reused. 精品文档 Example of an HTML Document html headtitleExample/title/head. body h1This is an example of a page./h1 h2Some information goes here./h2 /body /html 精品文档 Example of an XML Document ?xml version=“1.0”/ address nameAlice Lee/name emailalee@/email phone212-346-1234/phone birthday1985-03-22/birthday /address 精品文档 Difference Between HTML and XML HTML tags have a fixed meaning and browsers know what it is. XML tags are different for different applications, and users know what they mean. HTML tags are used for display. XML tags are used to describe documents and data. 精品文档 XML Rules Tags are enclosed in angle brackets. Tags come in pairs with start-tags and end-tags. Tags must be properly nested. nameemail…/name/email is not allowed. nameemail…/emailname is.