chapter 21 browsing the web 1. what’s inside and on the cd? in this chapter you will learn about:...
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Chapter 21Browsing the Web
1
What’s Inside and on the CD?
• In this chapter you will learn about:– The Web– Popular Web browsers– How to use a browser– How to find information– How to save and print information– How to download and stream files from the Web– How to respond to error messages
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What is the Web?
• The Web (“World Wide Web”) is a collection of data that can be linked and accessed using HTTP
• HTTP (“hypertext transfer protocol”) is the communication standard of the Web
• A Web page is a specially coded document that can contain text, graphics, videos, animations, audio, and interactive elements
• A Web server is a computer that runs special Web server software and can send Web pages via Internet
• A Web site consists of one or more Web pages located on Web server
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What is the Web?
• Each Web page is assigned a URL (“Universal Resource Locator”) that uniquely identifies its location – To access Web page, type its URL– Also click hypertext link – underlined word or phrase
– to access related documents• Web pages are created using HTML (“hypertext markup
language”), a set of specifications for creating documents that browse as Web pages
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What is the Web?
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What’s on the Web?
• The Web contains a variety of sites:– Commercial– Academic and research– Organizational and governmental– Search sites and portals– Social networking– Public forums– Media
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Which browsers are most popular?
• A Web browser is a program that runs on your computer and helps you access Web pages– Microsoft Internet Explorer– Mozilla Firefox– Google Chrome
• The browser you use depends on your computer platform and your personal preference
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Which browsers are most popular?
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How do I start my browser?
• To start Internet Explorer, click the icon
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How do I start my browser?
• If you want to display more than one Web page at a time, you can open another browser window or open another tab
• Hold Ctrl to keep a Web page open while linking another page
• Hold the Alt key to display the menu bar in Internet explorer
• Enter keywords in the Search box to search the Web
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How do I start my browser?
• The Refresh button requests a fresh copy of a Web page• Use the Stop button when a page takes too long to load• When using a dial-up connection, you can use the
Control Panel’s Connect to a Network option if your browser doesn’t automatically connect to the Internet
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How do I use a URL to go to a Web site?
• A URL serves as an address to uniquely identify a Web page
• Be very precise when entering a URL• A complete URL usually starts with http://• The part of a URL that appears after the dot indicates
the top-level domain
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How do I use a URL to go to a Web site?
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How do I use links on a Web page?
• A hypertext link (“link”) is a connection between two Web pages– Contains URL of Web page, so it can be used to
“jump” from one Web page to another– Links usually displayed on Web page as underlined
text or as graphic– When positioned over a link, arrow-shaped pointer
turns into– When you click a link, Web page displayed on
computer
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How do I use links on a Web page?
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How do I use links on a Web page?
• Text links often change color after clicked• To discover if graphic is link, move pointer over graphic
and see if pointer changes to hand shape• If browser is configured to display status bar, when you
move pointer over link, the link’s URL displayed in status bar
• Being aware of what’s shown in status bar lets you know link’s destination before you click it– Important for security
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How do the navigation buttons work?
• The Home button displays your home page• The Back button becomes enabled when you go to a
new page• The Forward button becomes enabled after you use the
Back button– The Forward button counteracts the Back button
• The Recent Pages list displays a list of Web sites visited during a session
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How do the navigation buttons work?
• The Address bar list keeps track of URLs that you’ve entered in the Address bar
• To change your home page, first make sure your browser is displaying the page you’d like to designate as your home page. Click the down-arrow next to the Home button and select Add or Change Home Page
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How does the Favorites list work?
• You can add a URL to a Favorites list or create a Bookmark so that you easily can access pages you frequently view
• Grouping favorites into folders can make it easy to locate the Web page you want
• To delete a Web page or folder from the Favorites list, right-click the page name, then click Delete on the shortcut menu
• Favorites can be shared
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How does the Favorites list work?
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How does the History list work?
• The History list displays titles and/or URLs of Web pages you visited in past
• You can empty the History list by clicking the Tools button and selecting Delete Browsing History
• You can configure Internet Explorer to set the number of days it retains entries in the History list– Click Tools– Click Internet Options– Click the General tab– Change the number in the Days to keep pages in
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How does the History list work?
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How does the History list work?
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How do I find information on the Web?
• The most popular way to find information on the Web is by using a search engine
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How do I find information on the Web?
• When entering keywords, be as specific as possible• The more keywords you use, the more targeted your
search becomes• Search engines provide tools for advanced searches• An exact-phrase search requires the search engine to
find pages that include a particular phrase with the words occurring in a specific order
• A Boolean search uses the operators (or symbols) AND(+), OR, and NOT(-)
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How do I find information on the Web?
• There are generalized search engines, special purpose search engines, and search-this-site technology
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How do I find information on the Web?
• You can find information using:– Web-based indexes– Lists of links– Links provided on the pages of wikis and other
documents• Not all information on the Web is reliable and accurate
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How do I find information on the Web?
• Factors that contribute to the quality of information:– Reliability– Bias– Accessibility– Professionalism– Search ranking– Venue– Validity– Completeness
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Can I save Web pages, graphics, and text?
• Use the Save As option on browser’s menu to initiate save
• Most browsers give you option of saving page as HTML file or as plain text
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Can I save Web pages, graphics, and text?
• Save a page as an HTML file if you want to use it as Web page or in browser– Saved file includes all HTML tags present in original– Alternatively, save page as plain text without
embedded HTML• Plain text file easier to read if opened with word
processing software• Also works better then HTML file if you want to cut
and paste to your own file
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Can I save Web pages, graphics, and text?
• Don’t have to save entire page on which graphic appears– Right-click Web page where graphic appears– Shortcut menu provides options checking graphic’s
file size and saving it
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Can I save Web pages, graphics, and text?
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Can I save Web pages, graphics, and text?
• Most photos and pictures on the Web are copyrighted– Save for personal use but get permission for
commercial or Web page use• Most graphics exist as either JPEG, GIF, or PNG files
– Use Properties option on shortcut menu to determine size
• Once saved, you can access it offline with browser or any graphics software that opens the type of graphic you saved
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Can I save Web pages, graphics, and text?
• To copy text from a Web page:– Select text by holding down mouse and dragging
from beginning to end– Click Page, then click Copy– Switch to program into which passage is going to be
copied– Use the program’s Paste command to complete the
operation
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How do I print a Web page?
• Most browsers make it easy to print using a toolbar button or menu option
• Some Web pages include a link to a “print friendly” version of page, designed to print on standard paper– Designed to use color in way that single page won’t
use all your printer ink– Look for “printer friendly” link before you start printout
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How do I print a Web page?
• For long Web pages:– Some browsers divide long web pages into series of
printable pages and let you select which to print– Others don’t have this capability
• Use copy and paste as described in “How do I copy text from a Web page?”
• To include the URL and title as header:– Click browser’s File menu– Click Page Setup– If using Explorer, make sure Header box contains
&w&u
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How do I download and stream files from the Web?
• The process for downloading data files is similar to downloading and installing software
• When you download a data file, you need to open the file with the appropriate application program
• Some downloadable files have been compressed• Check the file size before you start the download
process
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How do I download and stream files from the Web?
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How do I download and stream files from the Web?
• When you download a file and save it on your computer, you can access it whenever you like
• Streaming is a delivery method that plays music or displays a video in real time as it arrives from the Web to your computer
• While streaming takes place, parts of the media file might be temporarily stored on your computer
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How do I download and stream files from the Web?
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What should I do when I get an error message?
• If a Web page can’t be loaded, the browser eventually displays “Page Cannot be Found”– 404 error
• If a URL is not mistyped, the message probably means the page has moved, was renamed, or deleted
• Occasionally a message appears if the site is too busy to respond – try later
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What should I do when I get an error message?
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What should I do when I get an error message?
• Sometimes when a link is clicked, a message indicates a new location and you’re usually automatically redirected– If not, link provided to new location
• If a Web page appears garbled:– Might not have correct fonts installed– Web site might be in language browser doesn’t
support
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Why do browsers block pop-ups and ActiveX components?
• Most browsers are equipped to block activities that are annoying or could compromise your computer’s security– Pop-up ads are a pervasive type of online advertising
• A pop-up blocker prevents pop-up ads from appearing
– IE’s pop-up blocker can be turned on and off
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Why do browsers block pop-ups and ActiveX components?
– ActiveX components play media or run Web applications
• Can be legitimate or malicious– Legitimate components are signed and dated
• To adjust ActiveX settings, click the Tools button, select Internet Options, and then select the Security tab
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Why do browsers block pop-ups and ActiveX components?
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Is the Web safe?
• Some unscrupulous individuals try to take unfair advantage
• The Web, your browser, and common sense can make using Web safer than shopping at local mall or eating at local restaurant
• Most commercial Web sites encrypt sensitive information– URLs for secure Web connections begin with https
instead of http– Most browsers indicate secure site with padlock icon
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Is the Web safe?
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Is the Web safe?
• Some Web sites use cookies to keep track of each visitor by recording information about user
• A Cookie is small chunk of data generated by web server and stored on your computer’s hard disk
– Built in privacy features1. Information storied on your computer, not web
site2. Cookies only store information you provide3. Only accessed by Web site that created it
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Is the Web safe?
• Most browsers include security settings that allow you to block or delete cookies– Might not be able to make purchases at e-commerce sites– Good idea to delete old or unused cookies on regular
basis• Most browsers store copies of Web pages in browser
cache – temporary place to store something– Increases speed of loading page– Record of activities on Web– Cache safe but should be cleared when using public
computer, if concerned about privacy on own computer, or if short on hard disk space
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Is the Web safe?
• Antivirus software modules contain several defensive tools that block Web-based exploits
• Browsers and operating systems are updated frequently to parch security vulnerabilities
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