Introduction to Website Development

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13 Δεκ 2013 (πριν από 3 χρόνια και 9 μήνες)

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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


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


JavaScript, Perl, PHP, ASP, CFML


4
th

generation: Meta languages


SQL, HTML, XML


5
th

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

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 Header

]
-

Request


Line

]
-

Web browser (this is Netscape)

Command


URL



HTTP version

URL that contained the link to the requested URL

(Dennis, 2004 Figure 2
-
9)

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>

HTTP response from a Web
server


HTTP version Status code Reason

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.