Sunday, February 20, 2011

HOW THE WEB WORKS ? ? ? ? ? ?

The working of world wide web is based on client-server technology.The Internet user using a software known as a web browser requests a document located on the web.The browser makes the request to the Internet host  containing that document.
Thus a browser acts like a customer or client that requests for the information.The Internet host serves the information  and is thus called the server.
The flow of information is controlled by a protocol.The protocol used in this exchange is called HTTP.The client,or the user or web browser makes the HTTP request and is served by an HTTP server also known a web server.

  1. HTTP
  2. HTML
  3. URL's
     HTTP:-
              It is a set of rules  or protocol that governs the transfer of hypertext between two or more computers.The world wide web encompasses the universe of information that is available via protocol HTTP.

The exchange of information between client and server is controlled by a protocol called HTTP.The protocol transfers data in form of text,audio,video,images.
HTTP is called so because it is used in environment where there are rapid jump from one document to another .Thus , we can say that HTTP is the underlying protocol used by WWW which defines how much are formatted and transmitted and what action web server take in response to various commands.

Example:-When you enter a URL in your web browser this actually sends an HTTP command to the web server directing it to fetch and transmit the requested web page.


  HTML:-
            It stands for Hyper Text Markup language,it represents a way to take ordinary text and turn into Hyper Text,just by adding special elements called mark-up  tags that tell web browsers how to display a web page contents.The main goal of HTML is to be a universal language for classifying the function of different sections of a document.It is designed to work on a wide variety of platform .

HTML shares some important characteristics with its SGML parent:HTML is one member of a family of markup languages called SGML.

1)A character-based method for describing and expressing content.
2)A desire to deliver that content equally to multiple platforms.
 3)A method for linking document  components together to compose compound documents.

HTML  have different versions:
     1)HTML+
     2)HTML 2.0
     3)HTML 3.2
     4) HTML 4.0

URL's:-
         The term stands for Uniform Resource Locator.It is a string of characters that specify the address of a web page.A client that wants to access a web page needs an address.This  address of a web page is known as URL.The URL provides an addressing scheme which allows the browser to request just about any document or web page located anywhere on that document.A URL normally takes the form:
<protocol>://<web-server name>/<directory-name>/<file-name>
   or
http://www.yahoo.com/education/index.html

The first part of URL specifies the transfer protocol starting  at the leftmost portion of URL up to colon (:) tells the browser what type of server it will connect to and which protocol to use in order to retrieve / access the document,that is always represented by "//".

The second part of URL is full qualified domain name(FQDN) .It identifies the site running the server that controls the webpage the URL points to many sites.

The third part of URL identifies the full path name for a particular web page.The pathname is always preceded by single slash after the domain name.

Example:-http://www.microsoft.com/IE/index.html

TYPES OF URL
There are two types of URL
1)Absolute
2)Relative

Absolute URL use a complete Internet address to give the location of a resource.
Relative URL is not fully qualified but rather it inherits the protocol,host and path information from its parent document.








Friday, January 21, 2011

DIFFERENCE BETWEEN INTERNET AND WWW

HOW  INTERNET  DIFFERS FROM WWW

The information on the web is transported over the internet.The web therefore uses the Internet in fact , the web is driving force behind the Internet.

The WWW is the combination of 4 basic ideas:-

 1) HYPERTEXT :-
                            A format of information which allows one in a computer environment, to move from one part of a document to another or from one document to another document through internal connections among these documents called   HYPER-LINKS.

2) UNIFORM RESOURCE LOCATOR / IDENTIFIER :-
Unique identifier used to locate a particular resource ( computer file , document or other resource ) on the network.

3) THE CLIENT-SERVER MODEL OF COMPUTING :-
A system in which client-software or a client computer makes requests of server software or a server computer that provides the client with resources or services such as data or files.

4) MARK-UP LANGUAGE :-
Character or codes embedded in text which indicates structure semantic meaning an advice on presentation.




Friday, January 14, 2011

WORLD WIDE WEB

WORLD WIDE WEB

1) The WWW usually referred to as world wide web is a collection of files all over the world.These files represent text , documents , pictures , video , sounds , programs , interactive environment and just about any other kind of information that has ever been recorded in computer files.

2) The web is probably the largest and most diverse collection of information ever assembled.

3) The www is a global ,read-write information space.text documents , images , multimedia and many other item of information are identified by short unique identifier called URL so that each resource can be found  , accessed and cross-referenced in the simplest possible way.


4) On the WWW , a client program called a web browser retrieves information resources such as web pages and other computer files , from web server using their URL's and display them typically on a computer  monitor.One can then follow hyper linking in each page.


5) Other resources on WWW whose creation is provided by these hyper links.


6) It is also possible for example by filling in and submitting web forms to post information back to the web server for it to save or process in some way.


7) The following hyper links is often called "browsing" or "surfing" the web.

HOW THE WEB WORKS

The working of WWW is based on client-server technology .The Internet user using a software known as a web browser  requests a document located on the web.The browser makes the request to the Internet host containing that document.  
Thus a browser acts like a customer or client and requests for the information.The Internet host serves the information are is thus called server.
The flow of information is controlled by protocol.The protocol used in this exchange is called HTTP.
The client , or the user or web browser makes the HTTP request and is served by an HTTP server and also known as web server.






Saturday, January 8, 2011

Internet


INTERNET

It is very difficult to give the definition of INTERNET but in a general way it can be defined as an internetwork is a collection of individual networks,connected by intermediate networking devices,that functions as a single large network.Internet is network of network that connect computer all over the world.

Internet is a collection of globally connected people who are linked through computer,cables and telephone lines and communicating with each other in a common language for specific purpose.It is an unlimited commercial opportunity.



EVOLUTION OF INTERNET

Internet was started with the project called ARPANET which was sponsored by the United States Department Of Defence  , ARPA.The original idea was to build a network capable of carrying military and government information during a "nuclear event".
  
Till late 1970's ARPANET operated to provide connection facility to around a dozen of research sites.

Later in 1982,ARPANET established a TCP / IP protocol-a connection protocol between sites which is still in use today and is the primary method of connecting to the Internet.

In late1980's, the U.S. National Science foundation ,with its network of located computers, allowed people to share information from their home,institutions,offices, etc,...

The other networks which developed in parallel, like BITNET of IBM , X.25 based in Europe , and UUCP base in Bell Labs got slowly absorbed or got connected to Internet, in order to provide a unified information sharing medium.

Internet in India ,  was inaugurated on the auspicious day of Independence, i.e. ,15 August 1995.This in a way marks the inception of free flow from every corner of the world .
VSNL( Videsh Sanchar Nigam Limited) started a new service called GIAS (Gateway Internet Access Service) to Internet accessible to Indian users.

WORKING OF AN INTERNET

Information exists in the computer in the form of files.One of the key function in network of many computer is to move files between two specific computers.
For such a communication we require:-
1. The address of the destination
 2. A safe method of moving data in the form  of electronic signals.
This is done by TCP/IP for sending a large block of data to another machine,TCP divides the data into little packet.The role of IP is to put the destination-address information on such packets.The TCP/IP protocol suite consists of multiple protocols  each of which transfers data across the network in a different format and with different options.


APPLICATIONS OF INTERNET


It provides a variety of information to everybody ranging from entertainment to serious buisness application to areas of daily life such as:
1.Magazines and Newspapers         
2.Household items.
3.E-commerce
4.Education
5.Banking
6.Railway Reservation
7.On-line Shopping
8.Health Consultation
9.Buisness
10.Radio and T.V broadcasting
11.Entertainment
12.Research

Friday, January 7, 2011

WEB RELATED TERMS

Hey friends!!!!!!
         
 So,now we will start with some web related terms step-by-step :-

CONTENTS to be covered

1. Internet

2. World wide web

3. Idea of hypertext and hyper media

4. How the web works:-
                                     a)HTTP
                                     b)HTML
                                     c)URLs

5. Search engines

6. Hyper text markup languages                                  

7. Cascading style sheets ( CSS )

8. JavaScript

9. jQuery

After all these basic topics we will go in depth of various languages with their examples,explanation,programs (with their output),many more things..........
                                      

Thursday, January 6, 2011

WEB DEVELOPMENT



Hello friends!!
This blog is all about the various mark-up languages that we all come across while studying any web related subjects.This blog will help you to get more closer the world of web and various languages like HTML,XML, XHTML and many more such topics related to programming.We all know as in today's life it is very necessary to be well versed with the languages-be it client-side programming or server side programming like APPLETS ,SERVLETS ,ASP ,JSP like languages........


And yes students,it will become very easy for you to be in world of languages .But remember before getting into these languages we have to go through some web related topics................