1. Chapter 1 Introduction to Web Development

2. 2 Introduction to Web Development In 1990 and 1991,Tim Berners-Lee created the World Wide Web at the European Laboratory for Particle Physics (CERN) in Geneva, Switzerland The original purpose of the World Wide Web (WWW) was to provide easy access to cross- referenced documents that existed on the CERN computer network Hypertext linking allows you to quickly open other Web pages

3. 3 Introduction to Web Development (continued) A document on the Web is called a Web page A Web page is identified by a unique address called the Uniform Resource Locator (URL) A URL is also commonly referred to as a Web address A URL is a type of Uniform Resource Identifier (URI) A Web site refers to the location on the Internet of the Web pages and related files

4. 4 Introduction to Web Development (continued) Web pages are displayed using a program called a Web browser A Web server is a computer that delivers Web pages The most popular Web server software is Apache HTTP Server (Apache) The second most popular Web server is Microsoft Internet Information Services (IIS) for Windows

5. 5 HTML Documents Web pages are created using Hypertext Markup Language (HTML) Web pages are commonly referred to as HTML pages or documents A markup language is a set of characters or symbols that define a document’s logical structure HTML is based on an older language called Standard Generalized Markup Language (SGML)

6. 6 HTML Documents (continued) Like SGML, HTML was originally designed as a way of defining the elements in a document independent of how they would appear HTML has evolved into a language that defines how elements should appear in a Web browser Understanding HTML is critical in learning how to write a web application along with the server programming

7. 7 Basic HTML Syntax HTML documents are text documents that contain formatting instructions called tags HTML tags include: –Formatting commands (boldface or italic) –Controls that allow user input (option buttons or check boxes) Tags are enclosed in brackets ( ) and consist of an opening tag and a closing tag Tutorial for learning HTML –http://www.htmldog.com/http://www.htmldog.com/ –http://www.w3schools.com/html/DEFAULT.asphttp://www.w3schools.com/html/DEFAULT.asp

8. 8 Web Communication Protocols A Web page is identified by a unique address called the URL Each URL consists of two basic parts: –A protocol (usually HTTP) and –Either the domain name for a Web server or a Web server’s Internet Protocol address Hypertext Transfer Protocol (HTTP) manages the hypertext links that are used to navigate the Web

9. 9 Web Communication Protocols (continued) A host refers to a computer system that is being accessed by a remote computer A domain name is a unique address used for identifying a computer such as a Web server on the Internet The domain identifier identifies the type of institution or organization (.biz,.com,.edu,.org) An Internet Protocol, or IP address, is another way to identify computers or devices connected to the Internet

10. 10 Web Communication Protocols (continued) An IP address consists of a series of four groups of numbers separated by periods Each Internet domain name is associated with a unique IP address HTTP is a component of Transmission Control Protocol/Internet Protocol (TCP/IP) Hypertext Transfer Protocol Secure (HTTPS) provides secure Internet connections for transactions that require security and privacy

11. 11 Web Communication Protocols (continued) http://www.google.com/help/index.html Protocol Domain name Directory Filename Figure 1-4 Sample URL

12. 12 Publishing Your Web Site Web Hosting: –The publication of a Web site for public access –Internet access (cable modem, DSL, satellite, dial-up modem, ISP) Internet Service Provider (ISP): –Provides access to the Internet along with other types of services such as e-mail

13. 13 Publishing Your Web Site (continued) ISP advantages to hosting a Web site: –Extremely fast Internet connections using advanced fiber-optic connections –Large and powerful Web servers and the expertise and manpower to maintain and manage them A domain name is a unique address used for identifying a computer, such as a Web server on the Internet

14. 14 Publishing Your Web Site (continued) Domain name registration –Pick a domain name that is similar to your business name or that describes your Web site –You cannot use a domain name that is already in use or a trademarked name –Contact a domain name registrar to find out the availability of a domain name and register it –Domain names are stored in a master database that is maintained by the InterNIC

15. 15 Publishing Your Web Site (continued) Domain name registration (continued) –For a fee, domain names can be registered for a specified period of time –Most hosting sites provide registration service for you –After you register your domain name, notify your ISP of your domain information

16. 16 Publishing Your Web Site (continued) File Transfer Protocol (FTP) –Is a TCP/IP protocol used for transferring files across the Internet –Transfers files between an FTP client (your computer) and an FTP server (a server capable of running FTP) –The vehicle that allows you to get your Web page files to the Web server

17. 17 Publishing Your Web Site (continued) File Transfer Protocol (continued) –Your ISP provides a username and password to log on to the FTP site and upload files to the FTP server –Examples of FTP clients include Firefox and Internet Explorer and WinScp Use your browser to log on to an FTP server and upload your files

18. 18 Working with Well-Formed Web Pages HTML became an Internet standard in 1993 with the release of version 1.0 The current version of HTML (4.01) was released in 1999 HTML 4.01 is the last version of the HTML language and is being replaced with extensible hypertext markup language (XHTML) HTML is not suitable for user agents other than Web browsers

19. 19 XHTML Document Type Definitions (DTDs) A well-formed document must include: – declaration –,, and elements A document type definition (DTD) defines: –The elements and attributes that can be used in a document –The rules that a document must follow when it includes them

20. 20 XHTML Document Type Definitions (DTDs) (continued) There are three types of DTDs with XHTML documents: –transitional –strict –frameset The World Wide Web Consortium (W3C) was established in 1994 at MIT to oversee the development of Web technology standards

21. 21 XHTML Document Type Definitions (DTDs) (continued) The W3C: –Decided some common HTML elements and attributes for display and formatting would not be used in XHTML 1.0 –Recommended using Cascading Style Sheets (CSS) instead of HTML elements and attributes for displaying and formatting Web pages Elements and attributes that are considered obsolete and will eventually be eliminated are said to be deprecated

22. 22 XHTML Document Type Definitions (DTDs) (continued) Table 1-2 HTML elements that are deprecated in XHTML 1.0

23. 23 XHTML Document Type Definitions (DTDs) (continued) Transitional DTD: –Allows you to use deprecated style elements in your XHTML documents –Use only if you need to create Web pages that use the deprecated elements Frameset DTD: –Identical to the transitional DTD, except that it includes the and elements –Allows you to split the browser window into two or more frames

24. 24 XHTML Document Type Definitions (DTDs) (continued) Strict DTD: –Eliminates the elements that were deprecated in the transitional DTD and frameset DTD –The declaration for the strict DTD is as follows: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> –Always try to use the strict DTD

25. 25 Writing Well-Formed Documents Include a declaration and the,, and elements All XHTML documents must use as the root element XHTML is case sensitive All XHTML elements must have a closing tag Attribute values must appear within quotation marks

26. 26 Writing Well-Formed Documents (continued) Empty elements must be closed XHTML elements must be properly nested Nesting refers to how elements are placed inside other elements

27. 27 Cascading Style Sheets A single piece of CSS formatting information, such as text alignment, is referred to as a style The term cascading refers to the ability for Web pages to use CSS information from more than one source

28. 28 Cascading Style Sheets (continued) CSS properties: –CSS styles are created with two parts separated by a colon –The property refers to a specific CSS style –The value assigned to it determines the style’s visual characteristics –Together, a CSS property and the value assigned to it are referred to as a declaration or style declaration

29. 29 Cascading Style Sheets (continued) Inline Styles –Allow you to add style information to a single element in a document Internal Style Sheets –Create styles that apply to the entire document P { color : blue } selector property value External Style Sheets –A separate text document containing style declarations that are used by multiple documents on a Web site

30. 30 The Content-Type Element Create a content-type element to specify a content type that the document uses –The element provides information about the information in a Web page –The element is nested within the section of the Web page –The three primary attributes in the element are: name, content, and http-equiv

31. 31 Validating Web Pages A validating parser is a program that checks whether an XHTML document is well-formed and conforms to a specific DTD Validation verifies that your XHTML document is well formed and that the elements in your document are correctly written Validation can help you spot errors in your code XHTML validating services can be found online

32. 32 Understanding Web Development Web development, or Web programming, refers to the design of software applications for a Web site The Webmaster is responsible for: –The day-to-day maintenance of a Web site –Monitoring Web site traffic and ensuring that the Web site’s hardware and software are running properly –Knowledge of Web page design, authoring, and development

33. 33 Client/Server Architecture Server (“back end”): –A database from which a client requests information –Fulfills a request for information by managing the request or serving the requested information to the client –Responsible for data storage and management A system consisting of a client and a server is known as a two-tier system

34. 34 Client/Server Architecture (continued) Client (“front end”): –Presents an interface to the user –Gathers information from the user, submits it to a server, then receives, formats, and presents the results returned from the server

35. 35 Client/Server Architecture (continued) A three-tier, or multi-tier, client/server system consists of three distinct pieces: –Client tier, or user interface tier, is the Web browser –Processing tier, or middle tier, handles the interaction between the Web browser client and the data storage tier Performs necessary processing or calculations based on the request from the client tier Handles the return of any information to the client tier

36. 36 Client/Server Architecture (continued) Figure 1-16 The design of a three-tier client/server system

37. 37 JavaScript and Client-Side Scripting JavaScript is: –A client-side scripting language that allows Web page authors to develop interactive Web pages and sites –Used in most Web browsers including Firefox and Internet Explorer Client-side scripting is a language that runs on a local browser (on the client tier) instead of on a Web server (on the processing tier)

38. 38 JavaScript and Client-Side Scripting (continued) JavaScript allows you to: –Turn static Web pages into applications such as games or calculators –Change the contents of a Web page after a browser has rendered it –Create visual effects such as animation –Control the Web browser window itself

39. 39 Server-Side Scripting and PHP Server-side scripting refers to a scripting language that is executed from a Web server Hypertext Preprocessor (PHP) is a server-side scripting language that is used to develop interactive Web sites –Is easy to learn –Includes object-oriented programming capabilities –Supports many types of databases (MySQL, Oracle, Sybase, ODBC-compliant)

40. 40 Server-Side Scripting and PHP (continued) PHP (continued): –PHP is an open source programming language Open source refers to software where source code can be freely used and modified –Can’t access or manipulate a Web browser like JavaScript –Exists and executes solely on a Web server, where it performs various types of processing or accesses databases

41. 41 Server-Side Scripting and PHP (continued) General rule: Use client-side scripting to handle user interface processing and light processing, such as validation; use server-side scripting for intensive calculations and data storage Figure 1-17 How a Web server processes a PHP script

42. 42 Summary In 1990 and 1991,Tim Berners-Lee created the World Wide Web at the European Laboratory for Particle Physics (CERN) Transmission Control Protocol/Internet Protocol (TCP/IP) is a large collection of communication protocols used on the Internet A Document Type Definition (DTD) defines the elements and attributes that can be used in a document

43. 43 Summary (continued) Cascading Style Sheets (CSS) are a standard set by the W3C for managing the design and formatting of Web pages in a Web browser A system that consists of a client and a server is known as a two-tier system A three-tier client/server system consists of the client tier, the processing tier, and the data storage tier

44. 44 Summary (continued) JavaScript is a client-side scripting language that allows Web page authors to develop interactive Web pages and sites Hypertext Preprocessor (PHP) is a server-side scripting language that is used for developing interactive Web sites Open source refers to software for which the source code can be freely used and modified