The World Wide Web (www, W3) is an information system of interlinked hypertext documents and other digital resources that are accessed via the Internet.
It has become simply Web.
WWW-HISTORY
British computer scientist Tim Berners-Lee is the inventor of the Web. As a CERN employee, Berners-Lee distributed a proposal on 12 March 1989 for what would eventually become the World Wide Web.
The initial proposal intended a more effective CERN communication system, but Berners-Lee also realized the concept could be implemented throughout the world.
Berners-Lee and Belgian computer scientist Robert Cailliau proposed in 1990 to use hypertext "to link and access information of various kinds as a web of nodes in which the user can browse at will",and Berners-Lee finished the first website in December of that year.
The first test was completed around 20 December 1990 and Berners-Lee reported about the project on the newsgroup alt.hypertext on 7 August 1991.
WEB TERMINOLOGIES / CONCEPTS:
Client/server computing
The Web operates in the client/server model of computing .
- A client is a computer which requests computing services from another computer, known as a server.
- The client can be any computer but the server is always a computer that is specially devoted to providing services to client computers.
In the client/server architecture, a client can access many servers and a server can have many clients .This means that on the Web, a client computer can request information from different server computers at the same time .
Similarly, a server computer can provide information to different client computers simultaneously .
- The "fat server" or "thin client" approach places most of the processing functions on the server .
- The "fat client" approach places most of the processing functions on the client .
It is possible to automate the transmission of data from the server to selected clients using the "client pull" and "server push" mechanisms .
Web pages :
Web site
- "Client pull" uses a directive to instruct the browser to reload or update a document from the server at regular time intervals
- "server push" continually sends data to selected clients at specified time intervals
- this process usually continues for an indefinite period of time, until the server knows it is done sending data to the clients, or when the clients interrupt the process .
Web browsers
A Web browser is the interface between the user and the Web .
In the client/server model of computing of the Web, the browser is a client application.
The browser allows the client computer to request the service of one or more server computers by means of URLs .
- When a URL is entered in the location field of a browser, the browser goes through the following steps to establish the connection with the server:
- determine what protocol to use
- look up and contact the server at the address specified
- request the specific document from the server
- When the server has responded, the browser interprets and executes the HTML commands to display the returned text and images on a specific graphical user interface (GUI) platform (i.e. Windows, Macintosh or UNIX).
Web pages :
Hypertext documents , which are primarily text documents formatted and annotated with the Hypertext Markup Language (HTML).
Webpages may contain links to images, video, and software components that are rendered to users of a web browser application, running on the user's computer, as coherent pages of multimedia content.
Embedded hyperlinks permit users to navigate between web pages.
Web site
When multiple web pages are published with a common theme or within a common domain name, the collection is Web site.
Uniform Resource Locator (URL)
A standard way of specifying the location of a Web page, containing the hostname, "/", and a file.
HyperText Transmission Protocol (HTTP)
HyperText Transmission Protocol (HTTP) is the language by which computers in the Internet communicate with one another .
Connections between computers using this language are described as the "stateless" or "query-response" model of interaction .
- There is no permanent connection between the client and server computers.
- After a request has been made by a client, the connection is broken.
- Then a response from the server is sent back, and the connection is broken again.
- This process is repeated for every request and often even for a part of a request
HyperText Markup Language (HTML)
HyperText Markup Language (HTML) is the language used to write Web documents .
It is a language, but not in the sense of computer programming language such as FORTRAN, C and Visual Basic
It is aptly called a "language" because, just like natural human languages, it contains all the rules (grammar) and codes (words and phrases) necessary for the creation of a usable document .
It uses standard ASCII characters and contains formatting codes, called commands or tags , that describe the structure of a document, provide font and graphics information and contain hyperlinks to other Web pages and Internet resources .
Hypertext and hypermedia
Hypertext is the method by which hyperlinks (also called hotlinks) are incorporated in an HTML document that makes it possible to seamlessly refer to other HTML documents and retrieve information from them .
When text, image, audio and video files are linked together by means of hyperlinks, the term hypermedia is used instead.
By using hyperlinks, the Web allows a logical connection of files, in much the same way as the human brain links associated pieces of information with one another .
- A hyperlink is made up of two parts: an anchor and a pointer .
- the anchor appears on the computer screen as one or more underlined words.
- each anchor has a pointer in the form of a bookmark or a Uniform Resource Locator (URL)
- a bookmark is a pointer that allows the user to "jump" to a specific location in the same document by clicking the anchor.
- a URL is a pointer that enables the user to access other Web resources (i.e. text, image, audio and video files, as well as executable programs and other Internet protocols such as gopher, ftp, telnet and WAIS) in the same or a different server .
Plug-ins and helper programs
Plug-ins and helper programs are client-side applications developed to enhance the functionality of Web browsers .
A plug-in is a small application program that is installed to enable browsers to perform a specific function not supported by their generic capabilities.
Example: browsers support only certain bitmap or raster formats, plug-ins are required to display vector graphics.
Plug-ins are product-specific, i.e. a particular plug-in is developed and can be used for a specific software application only.
- Most plug-ins are free from software vendors.
- Netscape Navigator and Internet Explorer now contain basic plug-ins which are installed automatically when the browsers are installed.
- When the browsers requires a plug-in that has not yet been installed, it will prompt the user to download and install the plug-in .
- Plug-ins are loaded automatically when the browser is launched.
Example: browsers do not support video files, helper programs are required to display video files
Helper programs are product-specific, i.e. a particular helper program is developed and can be used for a specific software application only.
- helper programs are usually free from software vendors.
- helper programs are installed separately and are loaded automatically when they are needed by the browser
IMPORTANCE / ADVANTAGES OF WEB :
1. 24 *7 :
- Web and its business is open to the world 24 hours a day, 7days a week with no labor costs to watch it.
- An online store never closes.
- A website faces no time zone barriers.
2. Stability
- User may move their place of business, change the phone number, or even change hours, but the web never changes, and is always open.
3. Own Internet Identity
- Having an own domain name (www.yourcompany.com) establishes a strong online brand identity, and allows to set up email addresses specific to your own company.
- Today, email is the most common way to communicate efficiently and professionally with the rest of the world.
4. Customer Feedback
- User can gather information about your existing and potential customers by using online forms and surveys.
- Providing a feedback form to make it easy for customers to send their input.
- Conducting surveys to find out how to improve products and services.
- The site statistics are easy available on google and can also help understand how the visitors and customers use the site.
5. Worldwide Exposure
- There are numerous ways to promote a product or website to enhance prominence, drive targeted traffic, and get worldwide exposure for the business.
- User can register a site with various search engines and directories that reach more than 800 million Internet users around the world.
- Most of the search engines and directories allow free registration of websites.
- Leverage the massive reach of the Internet and the precision targeting of the search engines and directories.
- User can send press releases to news media about their business website that features unique aspects of the organization.
- Promote a site through free banner advertising on various link exchange networks.
APPLICATIONS -
1. Reach New Markets With a Global Audience
- Internet is the most cost effective way to trade nationally and internationally.
- A website will broaden your base of customers, members, distributors or suppliers.
- User can generate more and more clients for your business without doing additional marketing.
2. Create A Product Or Service Showcase
Providing photos and detailed descriptions of the products or services on web is easy .
3. Sell Products and Services Online
- Selling through a website is much cheaper and a great way to supplement your offline business.
- Providing secure online ordering is very affordable today.
4. Promote Services
- Lawyers, doctors, financial consultants, entertainers, realtors and all service oriented businesses should take advantage of the massive reach of the Internet.
- Millions of users are logging on to the Web to compare various specialists and practitioners before they purchase a specialized service.
WWW Prefix
1. Many hostnames used for the World Wide Web begin with www because of the long-standing practice of naming Internet hosts according to the services they provide.
2. The hostname of aweb server is often www, in the same way that it may be ftp for an FTP server, and news or nntp for a USENET news server. These host names appear as Domain Name System (DNS) orsubdomain names, as in www.example.com.
3. The use of www is not required by any technical or policy standard and many web sites do not use it.
4. Generally, the www prefix is not used when using subdomains. If user want to use the prefix with subdomain, make a vhost file and add this behavior as part of the domain configuration.
Use of the www prefix is declining as Web 2.0 web applications seek to brand their domain names and make them easily pronounceable.
As the mobile web grows in popularity, services like Gmail.com, MySpace.com, Facebook.com and Twitter.com are most often mentioned without adding "www." (or, indeed, ".com") to the domain.
The World Wide Web and the Internet
The World Wide Web is one of the protocols of the Internet.
The Internet is a super network made up of regional, national and international telecommunication networks linking together computers in educational institutions, government departments, military establishments as well as commercial and non-commercial organizations all over the world
Users of the Internet communicate by the following protocols:
- World Wide Web, a hypermedia system for delivering digital files in multiple forms, including text, picture, sound and animation
- file transfer protocol (ftp), for exchanging files between computers
- telnet, a log-on procedure for accessing programs on remote computers as though they were local
- electronic mail (e-mail) a mailing system whereby messages among Internet users, and among Internet users and users of networks outside the Internet, are delivered and exchanged
- gopher, a communication protocol for retrieving text- and file-based information distributed in different computers across the Internet
- newsgroups, discussion groups which contribute information to communities of users in a particular area of interest
- wide area information searching (WAIS), a distributed document retrieval system
