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 – http://en.wikipedia.org/wiki/Analytical_engine • 1 st generation (1950s): Machine language – 0s and 1s • • 2 nd generation (1960s): Assembly language • 3 rd generation (late 1960s): High-level programming – COBOL, Fortran, BASIC, Pascal, C, C++, Visual Basic, Java, C#

Scripting: 3.5

th generation

– • 4 th generation: Meta languages – SQL, HTML, XML • 5 th

JavaScript, Perl, PHP, ASP, CFML

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

1. Source code – Human-readable instructions using programming language 2. Compilation/Interpretation – • Compilation: All at once, in advance Most 3 rd generation languages and below – • Interpretation: Line-by-line, real-time All 4 th generation languages and above (including all scripting languages); also some 3 rd generation languages 3. Machine language – – Computer-readable ones and zeros Sometimes intermediary object code

The Internet

Internet Milestones

http://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

The World Wide Web

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

]-

Request

Date: Mon 06 Aug 2001 17:35:46 GMT

Line

User-Agent: Mozilla/6.0

]- Web browser (this is Netscape) Referer: http://www.indiana.edu/~aisdept/faculty.htm

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

Content-type: text/html

]- Type of file

]- URL

Allen R. Dennis

Welcome to the home page of Allen R. Dennis

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

Standards

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 1. Formal

: a standard developed by an industry or government standards-making body  e.g. USB, 802.11g, XML, CSS

2. 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

1. Specification

: developing the nomenclature and identifying the problems to be addressed.

2. Identification of choices

: identify solutions to the problems and choose the “optimum” solution.

3. 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

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.