Transcript Using the Web

Using a Web Browser
What does a Web Browser do?
A web browser enables you to surf the World
Wide Web.
What are the most popular browsers?
Functions of a Web Browser
•Designed to retrieve Web pages from Web servers on the
Internet.
•Uses HTTP(Hypertext Transfer Protocol) to connect and
communicate with the Web server on the Internet.
•The Web server sends the requested page to the browser
for display.
•In order to be displayed web page is written using HTML
(Hypertext markup language), and it might include text,
graphics, links to other Web pages, buttons, menus, or
checkboxes.
Functions of a Web Browser
Domain name
translated to IP address
172.23.63.144
HTTP
Yay! My page is
http://www.save
displayed in my
thecows.com
web browser!
Web server
HTTP
HTTP
Web page written
in HTML
Navigate the Web using a browser
•The browser opens to a preselected Web page called the home page.
You may change this page anytime you wish.
•To navigate to another web page when you know the URL use the
address box.
•You do not need to type the http part.
Temporary Storage of Web pages
Each time you request a Web page, your browser program saves
the page in a temporary storage area called cache. The Back
and Forward buttons enable you to move back and forward
through a sequence of Web pages you have already downloaded
and stored in the cache. The pages display quickly because your
browser retrieves them from the folder on your computer
instead of requesting a new copy from the Web server.
The Refresh button is used when you want to retrieve a new
copy of the Web page from the Web server instead of recalling
the copy it stored previously on your computer.
History of Web Pages
The browser keeps a list of Web pages you have
requested. This feature is useful if you do not
recall the address of a Web page but you know
approximately when you found it. You can set
the number of days that is included in the
history. You can also clear the history whenever
you would like.
Adding Functionality to the Browser
Some Web pages contain additional content
beyond the basics. To use those functions, the
browser program needs to be supplemented
with small accessory programs called plug-ins.
Examples of functionality that plug-in programs
provide are:
•Display special graphics files such as PDF
•Display video – Flash player, RealPlayer
Most of these programs are free downloads from a
provider’s website.
Searching for Information
•In 1992, it was possible to make a directory of the
Web pages that were available; there were only 30
websites.
•In less than two decades, the number of Web pages
has grown to more than 1 trillion and it is
impossible to review, index, and rank these pages
by having humans look at each one.
•Computer programs called Web crawlers or
spiders search for Web pages, examine the
contents of pages, and then report findings back to
a central computer that performs the indexing,
classifying, and ranking.
How do spiders work?
Search Engines
A search engine is the program that displays the Web page
that users use to make a request for a list of Web pages that
contain information related to their request.
When you ask a search engine to locate information, it is
actually searching through the index which it has created and
not actually searching the Web. Different search engines
produce different results because not every search engine
ranks, classifies, and indexes the same way.
Examples of popular search engines are Google, Yahoo!, Live
Search, and Ask.
How do Search Engines work?
Search Methods
•A keyword search is the method you use
when you begin searching for sites that are
related to a few individual words. These words
are called keywords.
•Search for wind turbine using Google.
Explore Advanced search.
•Demonstrate Ctrl+F
"Knowledge is of two kinds. We know a subject ourselves, or we know
where we can find information upon it."
--Samuel Johnson, 1744
Search tips
•Use the plus (+) or minus (-) in front of words to force their
inclusion and/or exclusion in searches.
Example: dolphins – miami
•Use double quotations (“ ”) around phrases to ensure they are
searched exactly as is, with the words side by side in the same
order.
Example: “green eggs and ham”
•Put your most important keywords first in the query
Example: dog breed family pet choose
•Search for synonyms using the tilde ~
Example ~cheap notebook computers
Web search strategies in Plain English
http://www.youtube.com/watch?v=CWHPf00Jkqg
Managing Information from a Website
•You can copy text and graphics from websites and
use them for other purposes.
•You can print a portion of a Web page. First, select
the text you want to print. In the Print dialog box,
in the Page Range section, click Selection, and then
click the Print button.
•You can also save an entire Web page to your hard
disk and view them with the browser. This enables
you to look at the saved pages even when you do
not have an Internet connection.
Searching Challenge
In groups of two or three find the answer to the following
question?
What U.S. President was arrested while in office for running
over an elderly lady with his horse?
The winner of the challenge will be the team that
locates a page with the answer with the least
amount of search results.