1. Chapter 1: Introduction to Web
Kingdom of Saudi Arabia
Ministry of Higher Education
Al-Imam Mohammad Bin Saud Islamic University
College of Computer and Information Sciences
Chapter 1: Introduction to Web
IS 203: Web Programming
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2. Information Systems Department
Table of contents
History of Web
Web System Architecture
URL
DNS
Protocols governing the Web
HTTP Request Response
Creating Static and Dynamic Websites
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3. Information Systems Department
History of Web
In the 1960's, Ted Nelson popularized the hypertext concept, and Douglas Engelbart created the first working hypertext systems.
In 1989, Tim Berners-Lee had suggested a way to let all users, but particularly scientists, browse each others’ papers on the Internet.
He developed HTML, URLs, and HTTP.
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4. Information Systems Department
What is a Web ?
The Web is a shared information space.
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5. Basic Web System Architecture
The web is a two-tiered architecture.
A web browser displays information content,
and a web server that transfers information to the client.
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6. Information Systems Department
Web Browser
The primary purpose is to bring information resources to the user.
An application for retrieving, presenting, and traversing information resources.
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7. History of Web Browsers

8. History of Web Browsers

9. History of Web Browsers

10. History of Web Browsers

11. History of Web Browsers

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Web Server
The term web server or webserver can mean one of two things:
A computer program that accepts HTTP requests and return HTTP responses with optional data content.
A computer that runs a computer program as described above.
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13. Basic Web System Architecture
This architecture depends on three key standards:
HTML for encoding document content.
URLs for naming remote information objects in a global namespace.
HTTP for staging the transfer.
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14. HTML Hypertext Markup Language
Document layout language (not a programming language)
Defines structure and appearance of Web pages

15. URL Uniform Resource Locator
URLs are location dependent
It contains four distinct parts: the protocol type, the machine name, the directory path and the file name.
There are several kinds of URLs: file URLs, FTP URLs, and HTTP URLs.

16. HTTP Hyper Text Transfer Protocol
HTTP is a request/response standard of a client and a server.
Typically, an HTTP client initiates a request.
Resources to be accessed by HTTP
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17. Information Systems Department
HTTP Request Methods
HTTP defines eight methods (sometimes referred to as "verbs") indicating the desired action to be performed on the identified resource.
HEAD
GET
POST
PUT
DELETE
TRACE
OPTIONS
CONNECT
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18. Sample HTTP Request and Response
Client request
Server response
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19. Web Architecture Extension
CGI extends the architecture to three-tiers by adding a back-end server that provides services to the Web server.
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20. Database Driven Website Architecture
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21. Server-side Processing
In server-side processing, the Web server:
Receives the dynamic Web page request
Performs all of the processing necessary to create the dynamic Web page
Sends the finished Web page to the client for display in the client’s browser
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22. Client-side Processing
Some processing needs to be “executed” by the browser, either to form the request for the dynamic Web page or to create or display the dynamic Web page.
Eg. Javascript code to validate user input
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23. Server and Client side processing
Server-side processing
PHP
ASP
ASP.NET
Perl
J2EE
Python, e.g. Django
Ruby, e.g. Ruby on Rails
ColdFusion
Client-side processing
CSS
HTML
JavaScript
Adobe Flex
Microsoft Silverlight
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24. Information Systems Department
Domain Name System DNS
Each host on the Internet has a range of IP (or Internet protocol) numbers.
The Domain name system (DNS) maps the numbers to names of hosts or websites (eg
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25. Protocols Governing the Web
TCP/IP, or Transmission Control Protocol-Internet Protocol. Essentially, TCP/IP describes a protocol which will work on any sort of computer and operating system for transportation of data across the internet between different systems. 
SMTP, or the Simple Message Transfer Protocol, is the basic standard for , and again exists since the 1980s when the Internet was small and honest.
Another important protocol which dates from pre 1972 is FTP, or the file transfer protocol. This simply is the way to upload or download a file from an Internet computer.
With the coming of the World Wide Web, we see another powerful protocol - http, or hypertext transfer protocol. HTTP allows us to click on the name of a site and visit it. Simple, but very powerful.
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26. Static vs Dynamic Sites
A static web site is a web site where the content, the HTML and graphics, are always static—it is served up to any visitor the same, unless the person who created the web site decides to manually change the copy of it on the server.
On a dynamic web site on the other hand, the content on the server is the same, but instead of just being HTML, it also contains dynamic code, which may display different data depending on information you feed to the web site. Another thing to note is that special software must be installed on the server to create a dynamic web site.
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