Web Introduction

Introduction to Website Development

ASIM SHAHZAD

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

• 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

http://en.wikipedia.org/wiki/Analytical_engine

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

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 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

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/)

http://www.zakon.org/robert/internet/timeline/

http://en.wikipedia.org/wiki/History_of_the_Internet

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

GET http://www.kelley.indiana.edu/ardennis/home.htm HTTP/1.1Date: Mon 06 Aug 2001 17:35:46 GMTUser-Agent: Mozilla/6.0Referer: http://www.indiana.edu/~aisdept/faculty.htm Request Header

]- Request Line

]- Web browser (this is Netscape)

Command URL HTTP version

URL that contained the link to the requested URL


HTTP/1.1 200 OK ]- Response StatusDate: Mon 06 Aug 2001 17:35:46 GMT ]- DateServer: NCSA/1.3 ]- Web serverLocation: http:// www.kelley.indiana.edu/adennis/home.htm ]- URLContent-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>

HTTP response from a Web server

HTTP version Status code Reason

Response Header

Response Body


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 best browser (in my own biased opinion)• Other browsers

– Apple Safari, 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, CSS2. 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)

http://standards.ieee.org/

http://www.ietf.org/

http://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

Thank you

Technology

Web Introduction