信息处理技术

1. 信息处理技术

2. Chapter 6: Web Pages, Web Sites, and E-Commerce Chapter 4: File Management, Virus Protection, and Backup Chapter 1: Computer, Internet, Web, and E-Mail Basics 1 1 1 1

3. Chapter 6 Preview After this chapter, you should be able to: • Describe the roles that HTML, XHTML, HTTP, URLs, browsers, and Web servers play in bringing Web pages to your desktop • Explain why cookies are useful in an environment that is based on a stateless protocol, and provide some concrete examples of their use • Identify some Web page design tools and discuss their advantages and disadvantages • Describe how HTML tags, cascading style sheets, links, buttons, hot spots, frames, forms, and tables are used in the design and creation of Web pages • Identify the elements that typically form a Web page Chapter 6: Web Pages, Web Sites, and E-Commerce

4. Chapter 6 Preview • Explain how to test and post Web pages • Describe how DHTML, XML, and XSL technologies work to enhance Web pages • List some advantages and disadvantages of using JavaScript, VBScript, Java applets, and ActiveX controls • Discuss why e-commerce has become so popular with consumers and merchants • List some threats to the security of credit card numbers and other sensitive data during e-commerce transactions • Describe how the following e-commerce technologies work: shopping carts, SSL, one-time use credit cards, electronic wallets, and person-to-person payment systems Chapter 6: Web Pages, Web Sites, and E-Commerce

5. Chapter 6 Outline • Section A • Web Technology • Section B • Basic Web Page Authoring • Section C • Web Page Extensions, Scripts, and Programs • Section D • E-Commerce Chapter 6: Web Pages, Web Sites, and E-Commerce

6. Chapter 6Web Pages, Web Sites, and E-Commerce 网页、网站及电子商务 Section A: Web Technology WEB技术

7. The Web, The Net, and Hypertext: What’s the difference between the Web and the Internet? • The Internet is a communications network • The Internet carries text, graphics, and audio data that forms Web pages • The Web is an interlinked collection of information that flows over the Internet Page 284 Chapter 6: Web Pages, Web Sites, and E-Commerce

8. What is hypertext and what does it have to do with the Web? • Two of the most important elements of the Web • Hypertext Transfer Protocol (HTTP) • Hypertext Markup Language (HTML) • Hypertext – text linked together in non-linear form • Hypertext link – clickable text that lets you access related documents Page 284 Chapter 6: Web Pages, Web Sites, and E-Commerce

9. What is hypertext and what does it have to do with the Web? Page 284 Chapter 6: Web Pages, Web Sites, and E-Commerce

10. How does the Web work? • Web pages are written in HTML • HTML document – plain text, or ASCII, document with embedded HTML tags • HTTP communications protocol is used by Web browser when requesting specific pages Page 285 Chapter 6: Web Pages, Web Sites, and E-Commerce

11. How does the Web work? Page 285 Chapter 6: Web Pages, Web Sites, and E-Commerce

12. HTML and XHTML: What is HTML? • HTML (Hypertext Markup Language)– is a set of specifications for creating documents • Tags specify how the document should appear • World Wide Web Consortium (W3C) – organization that reviews and revises HTML standard • XHTML is the follow-up version to HTML 4 Page 286 Chapter 6: Web Pages, Web Sites, and E-Commerce

13. HTML and XHTML: What is HTML? Page 286 Chapter 6: Web Pages, Web Sites, and E-Commerce

14. So HTML documents look a lot different than Web pages, right? • HTML document is like a screenplay • Web browser is like a director • Web page exists only for the duration of the performance Page 288 Chapter 6: Web Pages, Web Sites, and E-Commerce

15. Can I see the HTML tags used to create a Web page? Page 289 Chapter 6: Web Pages, Web Sites, and E-Commerce

16. What are the most commonly used HTML tags? • Formatting tags • Link tags • Media tags • Operational tags Page 289 Chapter 6: Web Pages, Web Sites, and E-Commerce

17. Web Browsers: Why do I need a web browser to access the Web? • Browser plays two roles: • Uses HTTP to send messages to a Web Server • Interprets the HTML tags from the Web server in order to display the requested Web page Page 289 Chapter 6: Web Pages, Web Sites, and E-Commerce

18. What are some of today’s most popular browsers? • Netscape • Internet Explorer • Opera • Mozilla Firefox Page 290 Chapter 6: Web Pages, Web Sites, and E-Commerce

19. Should I upgrade my browser when new versions become available? • It is a good idea to upgrade when a new version comes out • Contains up-to-date functionality • Some Web pages depend on new HTML features supported by newer versions of a browser • Upgrades are generally free Page 290 Chapter 6: Web Pages, Web Sites, and E-Commerce

20. Helper Applications, Plug-Ins, Players: Why do I have to download software to view some Web pages? • The native file formats for early browsers typically were limited to documents in HTML format and graphics files in GIF and JPEG formats • Files that are not handled by the browser sometimes require you to download helper application, plug-in, or player in order to handle the files Page 291 Chapter 6: Web Pages, Web Sites, and E-Commerce

21. What is a helper application? • A program that extends a browser’s ability to work with file formats • Updates your system so browser can automatically open helper application that works with a specific file format • Used by browser to open non-HTML file format Page 291 Chapter 6: Web Pages, Web Sites, and E-Commerce

22. Is a plug-in the same as a helper application? • Plug-in – type of helper application that can be activated by the EMBED tag inserted in an HTML document • Player – any helper application or plug-in that helps a browser display a particular file format Page 291 Chapter 6: Web Pages, Web Sites, and E-Commerce

23. HTTP: How does HTTP work? Page 292 Chapter 6: Web Pages, Web Sites, and E-Commerce

24. Does a browser have to request each Web page element separately? • Yes • HTTP is classified as a stateless protocol • One request and response per session • Assembly of one page requires one request per element on the page Page 293 Chapter 6: Web Pages, Web Sites, and E-Commerce

25. What if a Web server cannot find the file a browser requested? Page 293 Chapter 6: Web Pages, Web Sites, and E-Commerce

26. Web Servers: How does a Web server understand HTTP requests? • Web server is configured to include HTTP software • Always running when server is “up” and ready to fulfill requests • One port is dedicated to “listening” for HTTP requests • Traditionally port 80 Page 293 Chapter 6: Web Pages, Web Sites, and E-Commerce

27. Is a Web server the same as a Web site? • Not necessarily – server can house many sites or just one, and one site may cover several servers • www.hotmail.com – housed on several identically configured file servers Page 294 Chapter 6: Web Pages, Web Sites, and E-Commerce

28. Cookies: What is a “cookie”? • A small chunk of data generated by a Web server and stored in a text file on your computer • Web sites use cookies to: • Track your path through a site • Provide information that allows the Web site to present you with ad banners • Retain any personal information that you type into a Web page form Page 295 Chapter 6: Web Pages, Web Sites, and E-Commerce

29. What is a “cookie”? A cookie is created by a Web server and stored on your computer’s hard disk Page 295 Chapter 6: Web Pages, Web Sites, and E-Commerce

30. Are cookies safe and private? • Cookies are a relatively safe technology • Data, not computer program • Can only be accessed by site that created it • Contain only information you disclose while using the site • Uses a randomly generated number instead of your name Page 295 Chapter 6: Web Pages, Web Sites, and E-Commerce

31. Does my computer have to accept cookies? Page 296 Chapter 6: Web Pages, Web Sites, and E-Commerce

32. How long do cookies stay on my computer? • A Web programmer can program a cookie to “time out” • You can delete the cookies • Netscape uses Cookies.txt or Magiccookie • IE stores each in a separate file Page 296 Chapter 6: Web Pages, Web Sites, and E-Commerce

33. Chapter 6Web Pages, Web Sites, and E-Commerce Section B: Basic Web Page Authoring 网页设计基础

34. Web Page Authoring Tools:网页设计工具What tools can I use to create Web pages? • Text editor – most difficult as you have to create everything from scratch Page 299 Chapter 6: Web Pages, Web Sites, and E-Commerce

35. What is an HTML conversion tool?什么是HTML转换工具？ • Conversion option available in many software applications • Microsoft Word • File menu’s Save As Web Page • Online Web authoring tools • Provided by some ISPs • Type, select, drag, and drop elements onto Web page Page 300 Chapter 6: Web Pages, Web Sites, and E-Commerce

36. What’s Web authoring software?什么是网页设计软件？ • Web authoring software – provides tools for creating web pages • Microsoft FrontPage • Macromedia Dreamweaver Page 300 Chapter 6: Web Pages, Web Sites, and E-Commerce

37. What’s Web authoring software? Page 300 Chapter 6: Web Pages, Web Sites, and E-Commerce

38. What are the components of a Web page?网页页面的组成 Page 301 Chapter 6: Web Pages, Web Sites, and E-Commerce

39. Formats, Styles, and Style Sheets: How do I format the text on a Web page? • In Web page authoring software, highlight and then format • With a text editor, use tags such as: Page 302 Chapter 6: Web Pages, Web Sites, and E-Commerce

40. What is a style? • A style is the same as in the world of word processing • Bold, italic, green, and Arial • Don’t get carried away, choose base font for paragraphs; consistent style for headers Page 302 Chapter 6: Web Pages, Web Sites, and E-Commerce

41. What is a style sheet? • Cascading style sheet (CSS) – acts as a template that can control the layout and design of Web pages • Internal – placed near the beginning of html document (<style> tag within <head> section) • External style sheet – contains formatting specifications for a group of Web pages; a separate file contains the styles Page 302 Chapter 6: Web Pages, Web Sites, and E-Commerce

42. How are graphics incorporated into Web pages? Page 303 Chapter 6: Web Pages, Web Sites, and E-Commerce

43. What about video and animation? Page 304 Chapter 6: Web Pages, Web Sites, and E-Commerce

44. Links, Buttons, and Hot Spots: How do links work? • A link appears as underlined, blue text (color depends upon settings) • Can also be a button or a graphic • The HTML has two parts • Destination, Label Page 304 Chapter 6: Web Pages, Web Sites, and E-Commerce

45. How can I turn a graphic into a link? • Instead of text label, you can use an image as a clickable link • Can connect to graphics or other Web pages • Can look like buttons, complete with labels and icons Page 305 Chapter 6: Web Pages, Web Sites, and E-Commerce

46. What kinds of links can I add to a page? • Internal link – links to other pages on same site • External link – links to pages outside of the site • Intrapage link – jumps to a location within same page • Mailto link – automatically opens pre-addressed e-mail form that can be filled in and sent Page 305 Chapter 6: Web Pages, Web Sites, and E-Commerce

47. HTML Forms: What is an HTML form? Page 306 Chapter 6: Web Pages, Web Sites, and E-Commerce

48. What happens to the data that’s entered into a form? • Your information is stored in memory on your computer • When you click a Submit button, information is gathered and submitted via a specially designated program on an HTTP server Page 306 Chapter 6: Web Pages, Web Sites, and E-Commerce

49. What happens to my data after it arrives at a server? • CGI (Common Gateway Interface) – set of specifications or standards for how servers can handle a variety of HTTP requests • ASP (Active Server Pages) – server-side technology developed by Microsoft that offers an alternative to CGI • Runs on server and deals with data submitted • Can be written in any scripting language • CGI and ASP specify how the server should deal with the data Page 306 Chapter 6: Web Pages, Web Sites, and E-Commerce

50. Why are tables such an integral part of many Web pages? Page 307 Chapter 6: Web Pages, Web Sites, and E-Commerce