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Introduction to Website Development. Introduction. What is the World Wide Web? What is the Internet? What is a website? What is website development?. Computer programming languages. Generations of computer programming languages. Pre-computer age Babbage, Ada Lovelace
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Introduction • What is the World Wide Web? • What is the Internet? • What is a website? • What is website development?
Generations of computer programming languages • Pre-computer age • Babbage, Ada Lovelace • http://en.wikipedia.org/wiki/Analytical_engine • 1st generation (1950s): Machine language • 0s and 1s • 2nd generation (1960s): Assembly language • 3rd generation (late 1960s): High-level programming • COBOL, Fortran, BASIC, Pascal, C, C++, Visual Basic, Java, C# • Scripting: 3.5th generation • JavaScript, Perl, PHP, ASP, CFML • 4th generation: Meta languages • SQL, HTML, XML • 5th generation: Intelligent languages
Contemporary programming Languages • Traditional procedural (Third generation languages—3GL) • Basic, C, COBOL, Fortran • Script languages (3GL) • Perl, JavaScript, PHP, ASP, CFML • Object-oriented (3GL) • C++, Java • Visual and component-oriented (3GL) • Visual Basic, Visual C++, Delphi • Markup and modeling (Fourth generation languages—4GL) • HTML, XML, VRML • Data querying (4GL) • SQL • Web services (4GL) • Microsoft .NET, Java Web Services • http://en.wikipedia.org/wiki/Web_service
The program translation process • Source code • Human-readable instructions using programming language • Compilation/Interpretation • Compilation: All at once, in advance • Most 3rd generation languages and below • Interpretation: Line-by-line, real-time • All 4th generation languages and above (including all scripting languages); also some 3rd generation languages • Machine language • Computer-readable ones and zeros • Sometimes intermediary object code
Internet Milestoneshttp://www.zakon.org/robert/internet/timeline/http://en.wikipedia.org/wiki/History_of_the_Internet • 1969: Originally called ARPANET, the Internet began as a US military-academic network (originally 4 nodes) • 1974: TCP/IP developed; later becomes lingua franca of the Internet • 1983: Milnet (for military) split off. After, Internet used for academic, education and research only • 1986: NSFNet created as US Internet backbone • Around 1991: commercial access to the Internet begins. • 1993: NCSA Mosaic Web browser • As of 2004, the Internet had over 280 million servers and 934 million users. Growth in the use of the Internet continues at a rapid rate. (see http://www.clickz.com/stats/)
Internet services • WWW • E-mail • FTP • Others • Instant Messaging • Internet telephony • Usenet • Telnet
Open source software • Richard Stallman and the Free Software Foundation • The free software revolution • GNU and the General Public License • Copyleft • Linus Torvalds and Linux • Legitimization of the free software methodology • Eric Raymond and the Open Source Initiative • Free software becomes “open source” • Commercial legitimization of free software • Netscape and Mozilla • First major traditional enterprise to go open source • Mozilla Project successfully competes in consumer market
Background of the World Wide Web • 1989: Tim Berners-Lee invented HTML and the WWW • 1994: World Wide Web Consortium (W3C) established to guide Web standards • HTML: Standard WWW markup • XML: Customizable, data-oriented markup • XHTML: Extensible, well-formed HTML • CSS: Formatting
How the WWW Works (Dennis, 2004 Figure 2-8)
Example of an HTTP Request from a Web browser Command URL HTTP version GET http://www.kelley.indiana.edu/ardennis/home.htm HTTP/1.1 Date: Mon 06 Aug 2001 17:35:46 GMT User-Agent: Mozilla/6.0 Referer: http://www.indiana.edu/~aisdept/faculty.htm ]- Request Line ]- Web browser (this is Netscape) Request Header URL that contained the link to the requested URL (Dennis, 2004 Figure 2-9)
HTTP response from a Web server HTTP version Status code Reason HTTP/1.1 200 OK]- Response Status Date: Mon 06 Aug 2001 17:35:46 GMT]- Date Server: NCSA/1.3]- Web server Location: http:// www.kelley.indiana.edu/adennis/home.htm]- URL Content-type: text/html]- Type of file <html> <head> <title>Allen R. Dennis</title> </head> <body> <H2> Allen R. Dennis </H2> <P>Welcome to the home page of Allen R. Dennis</P> </body> </html> Response Header Response Body (Dennis, 2004 Figure 2-10)
History of web browsers • Initial, and text-only • NCSA Mosaic • First GUI browser, with images—gave a face to the Internet • Netscape Navigator • First commercial browser • Microsoft Internet Explorer • Today’s #1 browser in market share • Mozilla Firefox • The first successful open source browser • Other browsers • Apple Safari, Google Chrome, Opera, Konqueror
A grammatical note • “Web” or “web”, “Internet” or “internet”? • In English, you normally capitalize any noun that is unique in its entire domain, except when it is very commonly used • “The prime minister of India”—a description • But “the Prime Minister of India”—a title • “the Prime Minister”—unique, referring to the PM of Canada • “the Milky Way Galaxy”, but “the sun” and “the solar system” • Thus, it all depends on how unique and common you feel the Web and Internet are • My personal preferences: • I always capitalize “the Internet”, even as an adjective, as in, “Internet resources”. On the rare occasion that I refer to “the Net”, I also capitalize it. • The Web is more complicated: • The “World Wide Web” is always all capitalized • When referring directly to the WWW, I always capitalize “the Web” • When using the term as an adjective, I usually use small letters, as in “web resources”. • I spell “websites” and “webpages” as single words
Why Standards? • Standards provide a fixed way for hardware and/or software systems to communicate • For example, since XHTML is a standard, • Any web developer can create XHTML pages • that can be reliably served by any HTTP server • and that can be correctly viewed on any Web browser • at least, that’s the idea • By allowing hardware and software from different companies to interconnect, standards help promote competition
Types of Standards • Formal: a standard developed by an industry or government standards-making body • e.g. USB, 802.11g, XML, CSS • De facto: standards that emerge in the marketplace and are widely used, but lack official backing by a standards-making body • Intel 4x86 processor, Microsoft Windows, Macromedia Flash, Adobe PDF
The Standardization Processes:Three Steps • Specification: developing the nomenclature and identifying the problems to be addressed. • Identification of choices: identify solutions to the problems and choose the “optimum” solution. • Acceptance: defining the solution, getting it recognized by industry so that a uniform solution is accepted.
Some Major Standards Making Bodies • ISO: International Organization for Standardization (www.iso.ch) • ITU-T: International Telecommunications Union –Telecom Group (www.itu.int) • ANSI: American National Standards Institute (www.ansi.org) • IEEE: Institute of Electrical and Electronic Engineers (see standards.ieee.org) • IETF: Internet Engineering Task Force (www.ietf.org) • W3C: World Wide Web Consortium (www.org)
Components of website development • Content • Structure • Format and design • Dynamics and interactivity • Forms • Client-side programming • Server-side programming • Databases
Content • Purpose, goal and objectives of the site • Audience • Structure of content • Format and design of content • Interactivity and enhancement of content presentation
Structure • HTML vs. XHTML • HTML: Anything goes • XHTML: Strict conformation to standards • Internal file structure • Page sections • Templates • Site structure • Folder hierarchy • Content vs. resources • Maintaining file links
Format and design • Graphics and aesthetics • Functionality, usability, and accessibility
Dynamics and interactivity • Forms • Client-side programming • JavaScript, VBScript • Server-side programming • Perl, PHP, ASP, ASP.NET, ColdFusion, Python, JSP • Databases • MySQL, Access, Oracle, SQL Server
Summary • Computer programming languages of various generations and complexities are used for various purposes • The Internet connects computers worldwide to provide various information resources • The World Wide Web is the richest and most flexible Internet service • Standards are necessary to ensure a prolific and competitive atmosphere for web development • Components of website development: • Content • Structure • Format and Design • Dynamics and Interactivity
References • Dennis, Alan, 2002. Networking in the Internet Age. Wiley: New York.