2. History of World Wide Web:
In 1989-1990, Tim Berners-Lee invents the World
Wide Web at CERN.
It is published in 1992.
It is used for transferring text and graphics
simultaneously.
It is simple and easy to use.
3. What is World Wide Web?
The World Wide Web is a way of exchanging
information between computers on the Internet.
The World Wide Web can be viewed as a huge
distributed system consisting of millions of clients
and servers for accessing linked documents.
4. The WWW is essentially a huge client-server system
with millions of servers distributed world wide.
Each server maintains a collection of documents.
Each document is stored as a file.
A server accepts requests for fetching a document and
transfers it to the client.
6. Uniform Resource Locator:
The simplest way to refer the document is by means of
a reference called a “Uniform Resource Locator (URL)”.
It is defined as the global address of document and
other resource on the WWW.
A URL is one type of Uniform Resource Identifier
(URI) i.e; the generic term for all types of names and
addresses.
7. Document Model:
The Web is that all information is represented by
means of documents.
Some documents are as simple as an ASCII text file,
while others are expressed by a collection of scripts that
are automatically executed when the document is
downloaded into a browser.
Most Web documents are expressed by means of a
special language called HTML.
8. Simple HTML Program:
<html>
<body>
<H1> Hello World </H1>
<script type=“text/java script”>
document.writeln (“<H1>Hello World</H1>”);
</script>
</body>
</html>
9. Document Types:
There are many other types of documents besides
HTML and XML.
For example, a script can also be considered as a
document.
The other examples include documents formatted in
postscript or PDE, images in JPEG or GIF or audio
documents in mp3 format.
10. Communication:
All communications in the Web between clients and
servers is based on the HTTP.
HTTP is a relatively simple client-server protocol.
A client sends a request message to a server and waits
for a response message.
An important property of HTTP is that it is stateless.
11. Advantages:
Availability of mainly free information.
It helps us for fast browsing .
It provides security.
lt is accessible from anywhere, so it became the global
media.
