computer Unit 9

Internet and Designing Web Page
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Unit 9: Internet
Introduction
This learning unit provides information on Internet, email, web browsers
and basic elements of Web page design and layout. Evolution history of
Internet, advantages and way to access Internet are covered in Lesson 1.
World Wide Web, Some common terminologies and Email
communication system has been described in Lesson 2. In particular,
Lesson 3 discussed about the web browser. Introduction to some basic
design ideas and elements of web page design, text, colour, graphics and
assembling them as layout are described in Lesson 4. Lessons 5 of this
unit are devoted to the table and frame design. Lesson 6 explains a
combination of theory and practical hands-on activities.
Lesson 1: Beginning with Internet
1.1. Learning Objectives
On completion of this lesson you will be able to learn:
♦ what is Internet?
♦ history of Internet
♦ advantage of Internet
♦ how to access Internet.
1.2. What is Internet?
The Internet is a vast network that connects many independent networks
spanning over 170 countries in the World. It links computers of many
different types, sizes, and operating systems, and, of course, the many
people of those countries that use the Internet to communicate.
The one thing all these different computers have in common is the use of
the Internet Protocol, abbreviated as IP, which allows computers of
different types to communicate with each other. We will often see
reference to the longer abbreviation, TCP/IP, which stands for
Transmission Control Protocol/Internet Protocol. Your own computer
uses TCP/IP software to enable it to link to this service.
No organization, corporation or government owns or runs the Internet.
Instead, many people and organizations voluntarily participate in task
force groups who meet to develop standards for the many various
technical needs of running the Internet. Decisions are made by consensus

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among all who choose to participate, and every point of view is heard in
the long process of hashing out decisions and setting new standards.
1.3. History of Internet
The Internet was the result of some visionary thinking by people in the
early 1960s who saw great potential value in allowing computers to share
information on research and development in scientific and military fields.
J.C.R. Licklider of MIT, first proposed a global network of computers in
1962, and moved over to the Defense Advanced Research Projects
Agency (DARPA) in late 1962 to head the work to develop it.
In 1966 Lawrence Roberts of MIT developed his plan for ARPANET.
These visionaries and many more left unnamed here are the real founders
of the Internet. The Internet, then known as ARPANET, was brought
online in 1969 under a contract let by the renamed Advanced Research
Projects Agency (ARPA) which initially connected four major computers
at universities in the southwestern US (UCLA, Stanford Research
Institute, UCSB, and the University of Utah).
The Internet was designed in part to provide a communications network
that would work even if some of the sites were destroyed by nuclear
attack. If the most direct route was not available, routers would direct
traffic around the network via alternate routes.
The early Internet was used by computer experts, engineers, scientists,
and librarians. There was nothing friendly about it. There were no home
or office personal computers in those days, and anyone who used it,
whether a computer professional or an engineer or scientist or librarian,
had to learn to use a very complex system.
The Internet matured in the 70's as a result of the TCP/IP architecture
first proposed by Bob Kahn at BBN and further developed by Kahn and
Vint Cerf at Stanford and others throughout the 70's. It was adopted by
the Defense Department in 1980 replacing the earlier Network Control
Protocol (NCP) and universally adopted by 1983.
1.4. Advantage of Internet
The Internet makes it possible for us to communicate in various ways
and enables exchange of information and files. The most common things
we can do are:
Get information on almost any subject by searching the web. It takes
some skill to search efficiently. Since anyone can publish just about
anything, there is lots of misinformation on the web too.

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Send and receive email or chat or exchange messages with people all
over the world. Almost as fast as the telephone, there is never a busy
signal, and you never play phone tag.
Join discussion groups about a common subject with message
boards, Newsgroups and email discussion lists.
Get or exchange software and files with the File Transfer Protocol
(FTP)
Explore the World Wide Web, which can use all of the above, and
adds easy links to other resources and adds multimedia--graphics,
sound, and video capabilities.
Publish your own material on the web in blogs, message boards, or
your own web pages.
1.5. How to Access Internet
Internet access refers to the means by which users connect to the
Internet. Common methods of internet access include dial-up, landline
(over coaxial cable, fiber optic or copper wires), T- lines, Wi-Fi, satellite
and cell phones.

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Typical home user connection
Dial-up
DSL
Broadband wireless access
Cable modem
ISDN
Typical business connection
DSL
SHDSL
Ethernet technologies
Dial-up modems are generally only capable of a maximum bit rate of 56
kbit/s (kilobits per second) and require the full use of a telephone line—
whereas broadband technologies supply at least double this speed and
generally without disrupting telephone use.
Broadband Internet access, often shortened to just "broadband", is high-
speed Internet access—typically contrasted with dial-up access over a
modem. Various minimum speeds have been used in definitions of
broadband, ranging up from 64 kbit/s up to 1.0 Mbit/s.
An Internet service provider (abbr. ISP, also called Internet access
provider or IAP) is a business or organization that provides consumers or
businesses access to the Internet and related services. In the past, most
ISPs were run by the phone companies. Now, ISPs can be started by just
about any individual or group with sufficient money and expertise.

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1.6. Exercise
1. Multiple choice questions
1. IP stands for
a) Information Protocol
b) Internet Protocol
c) Information Processing
d) Internet Processing.
2. Internet was the result of some visionary thinking in the early
1960s by
a) Lawrence Roberts
b) Kahn
c) Vint Cerf
d) J.C.R. Licklider.
3. Which of the following is not a typical home user connection to
access Internet?
a) Dial-up
b) DSL
c) Broadband wireless access
d) Ethernet technologies.
4. ISP Stands for
a) Internet Service Provider
b) Internet Service Protocol
c) Information Service Provider
d) Internet Server Provider.
2. Short questions
1. What is Internet?
2. Who are the users of Internet?
3. What do you mean by Broadband Internet access?
3. Analytical questions
1. Write down the history of Internet.
2. State the advantages of using Internet.
3. Discuss method of Accessing Internet.

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Lesson 2: World Wide Web (WWW)
♦ common terminologies
♦ email communication.
2.2. Common Terminologies
Computer Network: A network is an interconnection of different
computing devices. These may include Desktop PC's, Servers, Routers,
Switches and also non traditional devices such as Personal Digital
Assistants (PDA), TV's, Mobiles etc. Computer networks may be
classified according to the scale: Personal area network (PAN), Local
Area Network (LAN), Campus Area Network (CAN), Metropolitan area
network (MAN), or Wide area network (WAN).
LAN: A local area network (LAN) is a computer network covering a
small geographic area, like a home, office, or group of buildings e.g. a
school. The defining characteristics of LANs, in contrast to Wide Area
Networks (WANs), include their much higher data transfer rates, smaller
geographic range, and lack of a need for leased telecommunication lines.
A network card: A network card, network adapter or NIC (network
interface card) is a piece of computer hardware designed to allow
computers to communicate over a computer network. It provides
physical access to a networking medium and often provides a low-level
addressing system through the use of MAC addresses. It allows users to
connect to each other either by using cables or wirelessly.
Repeater: A repeater is an electronic device that receives a signal and
retransmits it at a higher level or higher power, or onto the other side of
an obstruction, so that the signal can cover longer distances without
degradation.
Hubs: A hub contains multiple ports. When a packet arrives at one port,
it is copied to all the ports of the hub. When the packets are copied, the
destination address in the frame does not change to a broadcast address.
It simply copies the data to all of the Nodes connected to the hub.
Bridge: A network bridge connects multiple network segments at the
data link layer (layer 2) of the OSI model. Bridges do not promiscuously
copy traffic to all ports, as hubs do, but learn which MAC addresses are

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reachable through specific ports. Once the bridge associates a port and an
address, it will send traffic for that address only to that port.
Switch: Switches may distribute traffic on load or by application content
(e.g., a Web URL identifier). Switches may operate at one or more OSI
layers, including physical, data link, network, or transport (i.e., end-to-
end). A device that operates simultaneously at more than one of these
layers is called a multilayer switch.
Router: Routers are the networking device that forward data packets
along networks by using headers and forwarding tables to determine the
best path to forward the packets. Routers work at the network layer of the
TCP/IP model or layer 3 of the OSI model. A router is connected to at
least two networks, commonly two LANs or WANs or a LAN and its
ISP's network.
Protocols: Technical specifications or protocols describe how to
exchange data over the network.
OSI: Open Systems Interconnection, a joint ISO and ITU-T standard for
computer networks and communication protocols. The OSI reference
model was a major advance in the teaching of network concepts. It
promoted the idea of a common model of protocol layers, defining
interoperability between network devices and software.
Internet Protocol: The Internet Protocol (IP) is a data-oriented protocol
used for communicating data across a packet-switched internetwork. IP
is a network layer protocol in the Internet protocol suite. As a lower layer
protocol, IP provides the service of communicable unique global
addressing amongst computers.
Hyperlinks and URL: The World Wide Web is a huge set of interlinked
documents, images and other resources, linked by hyperlinks and URLs.
These hyperlinks and URLs allow the web-servers and other machines
that store originals, and cached copies, of these resources to deliver them
as required using HTTP.
HTTP: (Hypertext Transfer Protocol). HTTP is only one of the
communication protocols used on the Internet.
Web services: Web services also use HTTP to allow software systems to
communicate in order to share and exchange business logic and data.
User Agents: Software products that can access the resources of the Web
are correctly termed user agents.
Web Browser: Web browsers, such as Internet Explorer and Firefox
access web pages and allow users to navigate from one to another via

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hyperlinks. Web documents may contain almost any combination of
computer data including photographs, graphics, sounds, text, video,
multimedia and interactive content including games, office applications
and scientific demonstrations.
File sharing: A computer file can be e-mailed to customers, colleagues
and friends as an attachment. It can be uploaded to a Web site or FTP
server for easy download by others. It can be put into a "shared location"
or onto a file server for instant use by colleagues. The load of bulk
downloads to many users can be eased by the use of "mirror" servers or
peer-to-peer networks.
Optical Fiber: An optical fiber (or fibre) is a glass or plastic fiber
designed to guide light along its length. Optical fibers are widely used in
fiber-optic communication, which permits transmission over longer
distances and at higher data rates than other forms of communications.
Wireless LAN: Wireless LAN technology is built to connect devices
without wiring. These devices use a radio frequency to connect.
Wiki: In the early days, web pages were usually created as sets of
complete and isolated HTML text files stored on a web server. More
recently, web sites are more often created using content management
system (CMS) or wiki software with, initially, very little content.
2.3 Email Communication
First e-mail message was sent in 1971 by an engineer named Ray
Tomlinson. Tomlinson's breakthrough was the ability to send messages
to other machines on the Internet, using the @ sign to designate the
receiving machine.
Email is one of the earliest standard Internet protocols which enable
people with different computers and operating systems to communicate
with each other. E-mail allows one-to-one or one-to-many mailings. Mail
is received and held by a mail server within an organization or by an
Internet service provider until the addressee logs on to collect the mail.
An e-mail message has always been nothing more than a simple text
message sent to a recipient. In the beginning and even today, e-mail
messages tend to be short pieces of text, although the ability to add
attachments now makes many messages quite long.

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Two ways to access e-mail
1. Through browser by subscribing to free e-mail services like Hotmail
or Yahoo.
2. Through Stand-alone clients like Microsoft Outlook, Outlook
Express, Eudora.
Characteristics of e-mail access through browser software are as follows,
Can be accessed anywhere at any PC.
It is secured as user login every time to check or send mail.
This page can be speedily opened when server response time is high
and internet is available.
Characteristics of e-mail access through stand-alone software are as
follows,
Only can be configured in personal computers. Should not be used in
any PC.
Once configured it checks mail in every few minutes and stores
inbox in personal computer’s hard disk. Therefore user can view
them in convenient time.
It alert for every incoming mail.
If email server or internet traffic is slow it is a good alternative to
check mails as it checks for new mails when internet traffic is free or
server response time is high.
As it keeps every copy of mails sent or received in local computer
therefore, one safe to view any old mail if mail deleted or server is
not responding or internet is down for some period.
All incoming or outgoing mails are scanned with local antivirus
application loaded hence mails become virus free.
Any body other than the PC belongs to the person if uses computer
can open outlook express and view sensitive mails. Therefore user
must be more careful if he or she allowing someone else to use his or
her pc for a while.
No matter which type of client you're using, it generally does four things:
Shows a list of all of the messages in your mailbox by displaying the
message headers. The header shows you who sent the mail, the
subject of the mail and may also show the time and date of the
message and the message size.

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Let’s select a message header and read the body of the e-mail
message.
Let’s create new messages and send them. You type in the e-mail
address of the recipient and the subject for the message, and then
type the body of the message.
Let’s add attachments to messages you send and save the
attachments from messages you receive.
The real e-mail system consists of two different servers running on a
server machine. One is called the SMTP server, where SMTP stands for
Simple Mail Transfer Protocol. The SMTP server handles outgoing mail.
The other is either a POP3 server or an IMAP server, both of which
handle incoming mail. POP stands for Post Office Protocol, and IMAP
stands for Internet Mail Access Protocol.
Email Operation
Here we will see how to access your web mail account. Web mail allows
you to open your email at home or at work or from any computer
connected to the internet.
For web-based email first you type the URL (https://login.yahoo.com) in
your browser window. The screenshot below shows the Yahoo mail web
site.
Fig: Yahoo mail web site.

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You have to provide Yahoo ID and password information to access
your Yahoo email account. Then press Sign In button.
Your Inbox is automatically opened when you log-in. You will have
access to all your e-mail messages and folders that exist on the mail
server at the time of log-in. If you have created folders, they will be
listed on the left hand side. To access those folders, simply click the
folder name.
Fig: Yahoo mail Inbox window.
Inbox is automatically opened when you log-in. You will have access to
all your e-mail messages and folders that exist on the mail server at the
time of log-in. If you have created folders, they will be listed on the left
hand side. To access those folders, simply click the folder name. Note: If
you are using IMAP, you will have access to all your folders and e-mail
messages that you have stored on our e-mail server via this method. The
same folders and e-mail messages will be visible to you in your e-mail
program.
Yahoo mail saves incoming messages in the Inbox and outgoing
messages in the Sent box. You will need to create a folder by clicking
Add.
To write a new e-mail, click Compose.
To forward a message, open the message first and then click the
Forward button.
To delete a message(s), put a checkmark next to the message(s) and click
Delete.

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When you click the Compose button, you will see following screen in
your browser window.
Fig: Yahoo mail Compose window.
Enter the recipients full e-mail address in the ‘To:’, ‘cc’, or ‘Bcc’ field.
Enter a Subject (optional).
Type your message.
Click to check for any misspelled words.
Attach a file(s) (optional).
Click the Send button to send the message.

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When you click the Attach files button, you will seed following window,
Fig: Yahoo mail attach File window.
By clicking the Browse button, select the file(s) you want to attach and
then select Attach files button.
To read an e-mail, simply click on the message. The message will open
in the browser window. From the Read Message window, you can reply,
forward, delete, print, go to previous/next message in the current folder,
or save senders/recipients e-mail addresses in the Webmail Address
Book. Simply click the appropriate button.
To Add New Contacts just select a new contact in the address book,
enter the person’s information.
Logging Out: When you are ready to log out of Webmail, click on Sign
Out button, located on the top of the web page.

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2.4. Exercise
1. A local area network (LAN) is a computer network covering
a) campus area
b) metropolitan area
c) a small geographic area
d) wide area.
2. A network bridge connects multiple network segments at
a) the network layer
b) the data link layer
c) the physical layer
d) the session layer.
3. Which of the following sign is used to designate email address?
a) //
b) $
c) &
d) @.
4. Which of the following server handles outgoing mail?
a) IMAP server
b) POP3 server
c) Samba server
d) SMTP server.
2. Short questions
1. What is the function of a network card?
2. What are the functions of repeaters and hub?
3. Write down the characteristics of Bridge, Switch and router.
1. State the characteristics of accessing Email through browser
software.
2. State the characteristics of accessing Email through stand-alone
software.
3. Write down process of sending mail from your web mail
account.

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Lesson 3: Web Browsers
♦ web browser
♦ how do browsers work
♦ features of browsers
♦ microsoft Internet Explorer.
3.2. Web Browser
A web browser is a software application that enables a user to display
and interact with text, images, videos, music and other information
typically located on a Web page at a website on the World Wide Web or
a local area network. Most commonly used web browsers are,
Internet Explorer
Firefox
Safari
Opera
Netscape
Mozilla
3.3. How do Browsers Work?
Web browsers communicate with Web servers primarily using HTTP
(hypertext transfer protocol) to fetch WebPages. HTTP allows Web
browsers to submit information to Web servers as well as fetch Web
pages from them. The text document contains special instructions
(usually written in HTML) that tell the browser how to display the
document on the user's screen. The instructions may include references
(hyperlinks) to other web pages, information about text formatting and
color, and position information for images contained in the document.
The most commonly used HTTP is HTTP/1.1.
Pages are located by means of a URL (uniform resource locator), which
is treated as an address, beginning with http: for HTTP access. Many
browsers also support a variety of other URL types and their
corresponding protocols, such as gopher: for Gopher (a hierarchical
hyperlinking protocol), ftp: for FTP (file transfer protocol), rtsp: for
RTSP (real-time streaming protocol), and https: for HTTPS (an SSL
encrypted version of HTTP).

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The file format for a Web page is usually HTML (hyper-text markup
language) and is identified in the HTTP protocol using a MIME content
type. Most browsers natively support a variety of formats in addition to
HTML, such as the JPEG, PNG and GIF image formats, and can be
extended to support more through the use of plug-in. The combination of
HTTP content type and URL protocol specification allows Web page
designers to embed images, animations, video, sound, and streaming
media into a Web page, or to make them accessible through the Web
page.
Text and images on a Web page can contain hyperlinks to other Web
pages at the same or different website. Web browsers allow a user to
quickly and easily access information provided on many Web pages at
many websites by traversing these links. Web browsers format HTML
information for display, so the appearance of a Web page may differ
between browsers.
3.4. Features of Browsers
Browsers are the software that allows you to access the World Wide
Web. Most browsers contain the following features. Some of these may
be presented as buttons (or icons) in a toolbar. If you don't find a button,
you will find a menu item in one of the menus provided. You can usually
customize the toolbar to include any or all of these features:
Address Field
This area is where the URL (web page address) for the web page is
displayed or entered. In many browsers, there's a little downward facing
arrow next to this field. When you click on the arrow you will see a list
of recently visited websites. Clicking one of these URLs will take you to
that website. You can also enter a URL into this field and then press
enter or return to go to the website. In some browsers there is a "Go"
button next to this field that initiates a server request after typing in a
URL. By the way, you don't usually have to type in the "http://" part of
the URL. Most browsers will add that information in for you when you
press enter or return.
Back Button
Use this button to go back to the previous page opened in this particular
browser window. In some browsers, holding the mouse down on this
button produces a menu of previous pages that you can then choose
from. In other browsers, there's a little arrow next to the Back button that
produces this menu.

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Bookmarks or Favorites
You can easily create a shortcut to your favorite web pages by using the
Bookmark (or Favorites) menu or button. This is a very important feature
and it works a little differently in each browser. In Internet Explorer, use
the Favorites Menu to Add to Favorites. You can then use the Organize
Favorites menu item to place your bookmark in a folder or particular
place in the list. In Netscape, FireFox and Safari, choose Add Bookmark
from the Bookmark menu. You can then choose Show All or Manage
Bookmarks to create folders and/or rearrange your bookmarks. In most
browsers you can also place favorite websites to an area just above the
main browser window.
Close Box
This button in the upper right corner of the window will close the
browser window. If there is only one browser window open, the program
will exit. One way to tell if you have more than one browser window
open is to look at the button bar at the bottom of the screen. If you see
more than one button with the icon of the browser you are using, you can
switch between the open windows by clicking on these buttons. Another
way to deal with multiple windows is to minimize or Restore the window
to its pre-maximized size. On the Macintosh, there's a similar button, but
separate windows are more obvious and closing the last one does not quit
the browser.
Fonts or Larger or Smaller
In Internet Explorer a button called Fonts gives you a menu to choose the
size of the text displayed in the browser window. Some browsers offer
two buttons, Larger and Smaller to change the size of the text.
Forward Button
Like the Back button, the Forward button takes you to pages that you
have previously seen in a particular browser window. The Forward
button is only available if you have used the Back button and want to go
forward to where you were before. In some browsers, holding the mouse
down on this button produces a menu of previous pages, which you can
then choose from. In other browsers, there's a little arrow next to the
Forward button that produces this menu.

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History Button
Most browsers offers a History button or menu item which allows you to
look at the last several hundred web pages you've been to, and select one
of them for an easy return path.
Home Button
This button takes you to the page that has been designated as your
"home" page. You can select your "home page" in the browser's
Preferences (or Internet Options) section.
Favorites, Links or Personal Toolbar
You can add your own buttons to this toolbar. In Explorer it is called
Favorites or Links Toolbar and in Netscape it is called the Personal
Toolbar. These toolbars can be hidden or shown by using the View
menu.
Maximize Button
In Windows you can use this button to make the browser's window
enlarge to full screen. When the window is already maximized this
button is replaced by the Restore button.
Menubar
In Windows the Menubar is a part of each browser window. Choices
include File, Edit, View, History, Favorites or Bookmarks and Help. On
the Macintosh, these Menus are always at the top of the screen.
Minimize Button
In Windows you can use this button to make the browser's window
disappear from the screen. You can restore the window by clicking its
button on the bottom of the screen.
Print Button
You can print any web page by clicking this button.

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Reload or Refresh Button
If you suspect the contents of a browser's window may have changed
since the last time you viewed it, you should click the Reload or Refresh
button to update the page.
Restore Button
If the browser's window is maximized you can use this button to restore
the size of the window so that it no longer fills the entire screen. This is
very useful if you want to see more than one window at the same time.
Search Button or Field
In some older browsers there is a button to go to the page you have
designated as your "search" page. You can select your "search page" in
the browser's preferences section or by clicking the "Choose a Search
Engine" button in the Search window. Most browsers now have a search
field, at the right end of the main button bar, which you can type into to
perform Internet searches.
Security Indicators
Most browsers show a padlock icon in the lower left corner of the
window to indicate a secure connection. This means that data being sent
or received from that server is encrypted and would be extremely
difficulty for a third party to access. If this padlock is in the locked
position, you know you have a secure server connection. If the padlock is
unlocked, then you do not. Another way to tell is by the URL or web site
address. If the URL begins with https:// then the server connection is
secure.
Status Bar
The bar along the bottom of the browser's window shows you what is
being loaded into the browser window at the moment or the URL of the
link your mouse is over. There is usually also a progress indicator that
shows how much of a file has already been downloaded.
Stop Button
Use this button if you want to stop loading the contents of a page.

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Window Title
The title of the web page appears in the browser window's title.
Sometimes pages don't have titles. When you bookmark a page, the
window's title is used to identify the bookmark.
3.5. Microsoft Internet Explorer
Here is a screenshot of the Microsoft Internet Explorer.
Fig: An Online Journal webpage.

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3.6. Exercise
1. Which of the following is not a web browser?
a) Firefox
b) Safari
c) Gopher
d) Opera.
2. FTP stands for
a) File Transmission Protocol
b) File Transfer Protocol
c) File Transmission Process
d) File Transfer Process.
3. You can easily create a shortcut to your favorite web pages by
using
a) home Button
b) history Button
c) refresh Button
d) bookmark Button.
2. Short questions
1. What is the function of a Web Browser?
2. What types of information are contained in Web pages?
1. State how browser works.
2. Write down the features of a browser.

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