A web browser allows users to view and interact with web pages on the World Wide Web. It formats HTML content for display. Popular browsers include Internet Explorer, Firefox, Chrome, Safari, and Opera. A search engine is a program that helps users locate information on the web. It has three main components: web crawlers that gather page data, a database to store this indexed data, and a search interface for users. Popular search engines are Google, Yahoo, and Bing. A meta-search engine sends search requests to multiple other search engines and aggregates the results into a single list.

1. Working of web browser

2. Web browser
A Web browser is a software application which enables
a user to display and interact with text, images, videos,
music, games and other information typically located on
a Web page at a Web site on the World Wide Web or
a local area network.
Text and images on a Web page can contain hyperlinks to
other Web pages at the same or different Web site.
Web browsers allow a user to quickly and easily access
information provided on many Web pages at many Web
sites by traversing these links. Web browsers format
HTML information for display, so the appearance of a
Web page may differ between browsers.

3. Web browser
Web browsers are the most-commonly-used type of
HTTP user agent. Although browsers are typically used
to access the World Wide Web, they can also be used to
access information provided by Web servers in private
networks or content in file systems.
{A user agent is the client application used with a
particular network protocol; the phrase is most
commonly used in reference to those which access the
World Wide Web, but other systems such as SIP use
the term user agent to refer to the user's phone.}

4. Web browser
Current Web browsers
Some of the Web browsers currently available for personal computers include
1. Internet Explorer
2. Opera
3. Mozilla
4. Firefox
5. Safari
6. Avant Browser
7. Konqueror
8. Lynx
9. Google Chrome
10. Maxthon
11. Flock
12. Arachne
13. Epiphany
14. K-Meleon
15. AOL Explorer.

5. Internet Explorer
 Windows Internet Explorer (formerly Microsoft
Internet Explorer; (commonly abbreviated to IE), is a
series of graphical web browsers developed by Microsoft
and included as part of the Microsoft Windows line of
operating systems starting in 1995. It has been the most
widely used web browser since 1999, attaining a peak of
about 95% usage share during 2002 and 2003 with IE5
and IE6.
 The most recent release is version 7.0

6. Opera (web browser)
 Opera is a web browser and Internet suite developed by
the Opera Software company. Opera handles common
Internet-related tasks such as displaying web sites,
sending and receiving e-mail messages, managing
contacts, IRC online chatting, downloading files via and
reading web feeds. Opera is offered free of charge for
personal computers and mobile phones, but for other
devices it must be paid for
 Features of Opera include tabbed browsing, page
zooming, mouse gestures, and an integrated download
manager.

7. Mozilla Firefox
 Mozilla Firefox is a web browser descended from the
Mozilla Application Suite and man aged by Mozilla
Corporation
 Firefox includes tabbed browsing, a spell checker
incremental find, live bookmarking, a download
manager, and an integrated search system that uses the
user's desired search engine (Google by default in most
localizations).
 Firefox runs on various versions of Microsoft Windows,
Mac OS X, Linux, and many other Unix-like operating
systems. Its current stable release is version 3.0.7,
released on March 4, 2009.

8. AOL Explorer
 AOL Explorer, previously known as AOL Browser, is a
graphical web browser based on the Microsoft Trident
layout engine and was released by AOL. In July 2005,
AOL launched AOL Explorer as a free download and as an
optional download with AIM version 5.9. AOL Explorer
supports tabbed browsing

9. Avant Browser
 Avant Browser is a popular freeware web browser from
a Chinese programmer named Anderson Che, which unites
the Trident layout engine built into Windows with an
interface intended to be more feature-rich, flexible and
ergonomic than Microsoft's Internet Explorer (IE). It
runs on Windows 98 and above, including Windows Vista.
Internet Explorer version 6 or 7 must be installed.

10. Lynx (web browser)
 Lynx was a product of the Distributed Computing Group
within Academic Computing Services of the University of
Kansas, and was initially developed in 1992 by a team of
students at the university (Lou Montulli, Michael Grobe
and Charles Rezac) as a hypertext browser used solely to
distribute campus information as part of a Campus-Wide
Information Server. In 1993 Montulli added an Internet
interface and released a new version (2.0) of the
browser.
 Lynx was originally designed for Unix and VMS and is a
popular console browser on Linux. Versions are also
available for DOS, recent versions run on all Microsoft
Windows releases

11. Safari (web browser)
 Safari is a web browser developed by Apple Inc.. First
released as a public beta on January 7, 2003 on the
company's Mac OS X operating system, it became
Apple's default browser beginning with Mac OS X v10.3,
commonly known as "OS X Panther." Apple has also made
Safari the native browser for the iPhone OS.
 The current stable release of the browser is 3.2.1
(Macintosh) and 3.2.2 (Windows),

12. WEB Browser Detail
S.No Web browser Operating System
Support
Types Version
1 Internet Explorer Windows,Mac Graphical
based
7.0,6.0
2 Netscape
Navigator
Windows,Mac Graphical
based
7.0,7.2,8.0
3 Mozilla Firefox Windows Mac,Linux Graphical
based
1.0,2.0,3.0
4 Opera Windows,Mac,Linux Graphical
based
9.0,8.5,8.0
5 Lynx Windows,Mac,Linux
, Unix
Text based 2.0,2.8
6 Simple web 2000 Windows Voice based 2.0,3.0

13. SEARCH ENGINE
 A search engine is a program that helps the internet
user to locate information on the www. A web search
engine is actually a database that contains reference to
thousands of internet resources such as web pages.
 The users interact with these database by specifying
some keywords such as word or phrase. On the basis of
the keyword entered, search engine returns a list of
relevant pages from the database that matches the
search criteria.
 This information may vary from one search engine to
another

14. SEARCH ENGINE
 Generally there are three main components to a search
engine:
 Web crawlers: Web crawler is a software that constantly traverse
the web to gather information by following the links on the web
pages.
 Database : All the information that the web crawler retrieves is
stored in the database.
 Search Interface: The search interface component which is an
interface between the end-user and the database helps the user to
search through the database.
 Some popular web search engines are:
 Google
 Yahoo
 MSN Search
 Alta Vista

15. Searching the www
 Internet explorer has a built in search facility to perform
web searches via the search button on the standard toolbar
or by simply typing words into the address bar (auto search).
These search facilities helps us to search things easily.
 Searching using search button : in order to perform a web
search we just click on search button on the standard
toolbar in the internet explorer window.
 Auto search: in order to perform auto search we go to the
address bar and type find India hostels, go India hostels.
The internet explorer will automatically send your queries to
a search service and display a list of search results. You can
choose from the list by scrolling the list.

16. Web Directory
 Web Directory is a highly structured way of searching
information on the www. A web directory is also known
as indexes or catalogues.
 Web directories organize there resources using
hierarchical tree structure, moving from general
structure category to a more specific one. Web
directories may be organized in a variety of ways such
as alphabetically or topically .
 Web directories are hypertext links to present there list
resources. When a user click on a particular category in
the web browser then he is presented with a series of
links to the sub categories. This process continue until
you get the desired category of interest.

17. Working of a search engine
 Now describe how a search engine works. We split up its
functions into a number of components: User Interface,
searcher and evaluator.
 User Interface: the screen in which you type a query and
which displays the search result.
 Searcher: the part that search a database for information to
match your query.
 Evaluator: the function that assigns relevancy scores to the
information retrieved.
 Gatherer: the component that traverses the web, collecting
information about pages.
 Indexer: the function that categorizes the data obtained by
the gather and creates the index.

18. Metasearch engine
meta-search engine is a search tool that sends user
requests to several other search engines and/or databases
and aggregates the results into a single list or displays
them according to their source.
Metasearch engines enable users to enter search criteria
once and access several search engines simultaneously.
Metasearch engines operate on the premise that the Web
is too large for any one search engine to index it all and
that more comprehensive search results can be obtained
by combining the results from several search engines. This
also may save the user from having to use multiple search
engines separately.

19. Metasearch engine
The term Metasearch is frequently used to classify a set
of commercial search engines, see the list of search
engines, but is also used to describe the paradigm of
searching multiple data sources in real time. The National
Information Standards Organization (NISO) uses the
terms Federated Search and Metasearch interchangeably
to describe this web search paradigm.

20. Metasearch engine

21. search engines work
Search Engines per definition are information retrieval
system designed to help find information stored on a
computer system.
A search engine consist of three parts
First part is the spider which is also called the crawler or
bot. This spider part visits a web page, reads it, and then
follows links to other pages within the site. This process is
often referred to as crawling or spidering.

22. search engines work
Crawling of a website is done on a very regular basis,
frequency of which is determined by the frequency with
which website adds the content. It can vary from once in a
month to several times in a day.
The spiders visit a website following links from other
website or website submission it received.
The content that spider find is sent to its database or
index as it is popularly known. This index is like a huge book
that contains a copy of web page or cache, that the spider
finds out. This constitutes second part of a search engine.

23. search engines work
It also stores the structure and the way pages are linked to
each other. This information would be updated every time
there is a change in content or linking.
There could be interval between spidering and indexing
which varies from site to site and engine to engine. But
until indexed, the web page would not be available for the
search terms.

24. search engines work
Third part of a search engine is search engine software
that works behind the interface when we use a search
engine. This software will sift through the trillions of
indexed pages to match the search query that user has
asked. The pages are ranked by search engines and the
search results are based on this ranking and relevance to
search term. This is how a search engine determines what
order shall be listed for a particular search.