Using the Web

Using a Web BrowserWhat 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

http://www.savethe

cows.com

HTTP

Web server

Web page written in HTML

HTTP

Domain name translated to IP address

HTTP172.23.63.144Yay! My page

is displayed in my web browser!

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 pagesEach 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 PagesThe 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 BrowserSome 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 EnginesA 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 queryExample: 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 ChallengeIn 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.