computer concepts 5th edition parsons/oja page 272 chapter 6 web technology section a parsons/oja...

Computer Concepts 5th EditionParsons/Oja

Page 272

CHAPTER

6

Web TechnologySection A

PARSONS/OJA

Web Pages, Web Sites, And E-Commerce


73

Chapter

6Chapter PREVIEW

Web Pages, Web Sites, and E-Commerce

Elements of web pages Cookies Spyware Cache storage of web pages viewed Web page design tools Identify the elements of a web page E-commerce

Security Shopping carts Taxation


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Chapter

6Chapter PREVIEW

Web Pages, Web Sites, and E-Commerce

The good… Telecommuting Online learning Videoconferencing

The bad and ugly… Online gambling Plagiarism

The questionable… Internet censorship


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6Web Technology

Should I upgrade my browser when new versions become available?

Usually, it is a good idea to upgrade when a new version comes out Contain up-to-date functionality Some Web pages depend on new HTML

features supported by newer versions of a browser

Internet Explorer and Netscape are free and so are the upgrades

Best viewed with…


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Helper Applications, Plug-Ins, Players: Why do I sometimes see a message that tells me to download some player in order to view a Web page?

Browser interprets HTML Files that are not handled by the browser;

sometimes require you to download helper application, plug-in, or player in order to handle the files


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What is helper application?

Helper application – program that understands how to work with a specific file format Updates your system so browser can

automatically open helper application that works with a specific file format

Used by browser to open non-HTML file format

• Adobe Acrobat


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Is a plug-in the same as a helper application?

Plug-in displays files within the browser window Helper application displays files in new window Player – any helper application or plug-in that

helps a browser display a particular file format


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How do I know which players are installed?

Netscape provides a list IE doesn’t provide a list, but you can see the list

in the Control Panel’s Add/Remove Programs icon Turf war to be your default player… Select custom installation?


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How do I know which players are installed?


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Does a browser have to request each Web page element separately?

Yes. HTTP is classified as a stateless protocol

One request and response per session Assembly of one page requires one request

per element on the page• Easy to believe with a dial up modem


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What if a Web server can’t find the file that a browser requested?


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Can a Web server accommodate more than one request at a time?

A single port can connect to many sockets at a time Depends on server’s memory and operating

system (at a minimum – hundreds of requests) Denial of service attacks

Server farm – group of multiple servers that handle thousands of requests that come in each second


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Cookies: What is a “cookie”?

Cookie – small chunk of data generated by a Web server and stored in a text file on your computer

Cookie: [email protected]/

SITESERVER ID=9022591d2390f3b8639aa3c7cf1ca8f5 sarasota.fl.us/ 0 642859008 31887777 2868194304 29411026


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What is a “cookie”?

Web sites use cookies to: Track your path through a site Provide information that allows the Web site to

present you with ad banners• Relevant to you

Retain any personal information that you type into a Web page form


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6Web Technology

Why do Web sites use cookies to keep track of my activity?

Because each request is considered separate by the Web server

Cookies allow server to know which requests are yours Provide temporary storage space

Way to identify your requests from others


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Are cookies safe and private?

Cookies are a relatively safe technology Data, not computer program Can only be accessed by site that created it Contain only information you disclose while

using the site Uses a randomly generated number instead of

your name


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Does my computer have to accept cookies?


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6Web Technology

Does my computer have to accept cookies?

Most browsers will let you block cookies, but for many Web sites, cookies are only mechanism for tracking your activity or remembering purchases Without cookies, you may not be able to do

some things on the Web You may also require approval of cookies


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How long do cookies stay on my computer?

A web programmer can program cookie to “time out”

You can delete the cookies Netscape uses Cookies.txt or Magiccookie IE stores each in separate file Loose your identity


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Spyware

Advertising supported software Results in pop-up ads related to your web surfing

activities The program continuously reports your activity at

web sites to a central database Privacy issue… Deluge of pop up ads Anti-spyware software


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Another privacy issue…cache storage of web pages

Web browser stores previously viewed web pages on hard drive

Grandma knows… Settings prevent this folder from eating up your

hard drive Not a bad idea to periodically empty this folder


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Monitoring employees computer usage

Software allows system administrators to view: who is using networked computers what they are doing on the computers how long they spend count keystrokes

Generally, no regulations in this area Individuals fired for sending offensive e-mails

Arcola police chief forwarding e-mails about mayor Companies feel they must do this to prevent lawsuits and

slacking Consulting company has employees wearing bar code

scanners


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6Basic Web Page Authoring

Basic Web Page Components: What can I put on a Web page?

Head section – begins with <Head> and contains: Title of your page as it will appear in the title

bar of your browser window Global formatting information Information about your page that can be used

by search engines• Very important for commercial sites

Scripts that add interactivity to your page


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What can I put on a Web page?

Body section – begins with <body> tag and contains: Text that you want to display HTML tags that format the text Variety of links (including graphics and

sounds) Web page header – subtitle that appears in a

font that is different style than normal text


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What can I put on a Web page?


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What kinds of links can I add to a page?

Internal link – links to other pages on same site External link – links to pages outside of the site Interpage link – jumps to a location within same

page mailto link – automatically opens pre-addressed

e-mail form that can be filled in and sent


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What is a broken link?

Broken link – non-functioning link Can occur if webmaster moves requested file,

deletes it, or changes its name 404 Page Not Found Broken link icon


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Testing and Posting Web pages: How do I get my pages on the Internet?

1. Test each page locally

2. Transfer pages to a Web server

3. Test all links 4. Update your site to

keep it current


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6Web Page Extensions, Scripts, and Programs

How would a Web page author use a scripting language?

Scripting languages allow pages to become more interactive Allows e-commerce sites to verify credit card

information Makes interactive pages like loan payment

calculators


5

Section CChapter


ActiveX controls: What is an ActiveX control?

ActiveX control – compiled computer program that can be referenced from within an HTML document Can be used on client-side or server-side


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What is an ActiveX control?


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Are ActiveX controls safe?

Most are safe, but ActiveX controls are full-fledged programs Can include routines that alter or delete data

on your computer’s hard disk You can modify IE so that it never downloads any

ActiveX controls


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Are ActiveX controls safe?


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What is a digital certificate?

Digital certificate – electronic attachment to a file that verifies the identity of its source

Certificate authority – company that supplies digital certificates


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How does a digital certificate work?

If your security is set to “medium”, browser displays a warning message to alert you that an ActiveX component is trying to install itself

Your browser reads the certificate, displays the name of the person or company that signed it, and verifies that the component was not altered since it was signed


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How does a digital certificate work?


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6E-Commerce

E-Commerce Basics: What is e-commerce?

E-commerce – describes financial transactions that are conducted over a computer network Includes physical products, digital products, and

services Digital products such as News, music, video,

databases, software, and all types of knowledge-based items

• Will they ever figure out music??? Peddle services, such as arranging trips, online

medical consultation, and remote education Carried out by computer or require human agents


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6E-Commerce

Who is the typical e-commerce customer?

Demographics not yet stabilized In 1995, 30-something white male Now, females and teens have entered the

online shopping fray in droves B2C (business-to-consumer) e-commerce –

typical e-commerce activities that the typical Web surfer enjoys. Amazon.com

C2C (consumer-to-consumer) – includes online auctions and rummage sales. Ebay


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6E-Commerce

What makes e-commerce so special?

Customers can easily search through large catalogs Can configure products online Can see actual prices Can build an order over several days

Allows merchants to attract customers Global market Can track customer preferences and produce

individually tailored marketing


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6E-Commerce

How does e-commerce work?


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6E-Commerce

How does e-commerce work?

Shoppers connects to online store Based on domain name which acts as the entry

to the online store Includes some mechanism for customers to

select merchandise and then pay for it


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6E-Commerce

How do shopping carts work?

Shopper browses Web site, and then adds products using a “Buy” or “Add to Cart” button

Uses cookies to store information about your activities on Web site


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6E-Commerce

How do shopping carts work?


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6E-Commerce

What is an HTML form?


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6E-Commerce

What happens to the data that’s entered into a form?

Your information is stored on your hard disk; it not left “hanging around”

When you click a Submit button, information is gathered and submitted via a specially designated program on an HTTP server


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6E-Commerce

Can the data in the HTTP message be intercepted in transit?

Packet sniffer – monitors data as it travels over networks

2 technologies protect the data SSL (Secure Sockets Layer) – encrypts the

data • Indication of secure connection in web browser

S-HTTP (secure HTTP) – extension of HTML that encrypts the text of an HTTP message before it is sent


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6E-Commerce

Credit Card Security: How can online credit card transactions get hacked?

Fake Storefronts – Trojan horse site Intercepted packets – uses packet sniffers Database break-ins – unauthorized access of

customer databases Dishonest employees Always-on connections


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6E-Commerce

Encryption

Disguising the contents of a message Recipient must have a key to verify message Federal government wants a second key they

can use Export restriction on encryption software


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6E-Commerce

What steps can I take to safeguard my credit card number?

Only foolproof method – don’t use it To reduce probability of online credit card fraud,

make sure that you deal with legitimate merchants

Limits on credit card liability


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6E-Commerce

Person-to-Person Payment Services: What is a person-to-person payment?

Person-to-person payment – offers alternative to credit cards PayPal

Customer opens an account, deposits money to account using credit card

Customer receives user ID and password Money can be sent to anyone who has an e-mail

account


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6E-Commerce

Is person-to-person payment safe?

Advantage – only payment service sees your credit card numbers

Still in its infancy, and companies are still scrambling to offer reliable, long-term service to customers Unregulated Sometimes go out of business without

providing notice Consumer advocates recommend using these

services with caution, and keeping account balances low


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Payment of sales taxes on Internet purchases

Currently payment of sales taxes is generally not required on Internet purchases Promote growth of Internet

Companies, particularly amazon.com, maintain too complex to collect sales taxes Different taxing jurisdictions

Competitive advantage for online retailers


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6World Wide Web

Telecommuting

Advantages Increases productivity

• No commute• No interruptions

Flexible hours Balance family life Good for environment

• Less traffic Disabled

Disadvantages Self-motivated Social interaction


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6World Wide Web

Online learning

Advantages Convenience

• Asynchronous• Determine pace• Geography not an issue

Peer to peer learning Writing skills

Disadvantages Self-motivated Communication with peers Social interaction High drop rates


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6World Wide Web

Videoconferencing

Reduce travel $10,000 annual cost to install, train and operate

system Rent: $175 per hour

Savings in terms of• Time

• Travel costs

• Peace of mind


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6World Wide Web

Online gambling

Currently not regulated Convenience Credibility of casino

Registered with Interactive Gaming Council?? Women???


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6World Wide Web

Plagiarism

Failure to acknowledge source of information Much easier with advent of Internet

Many pages of information available Copy and paste Napster-like services


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6World Wide Web

Plagiarism

downloaded from pay sites Busted!!

• reference to mystery teachers

• printing from a browser window

• reference to past truths as true now (current president)

• perfect paper


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6World Wide Web

Plagiarism

Eve2, uses a search engine format to suggest what site a paper may have come from.

scanning the net for sentences or other bunches of consecutive words and providing a link for the instructor to further investigate.

Gives a percentage of work plagiarized and highlight in red the areas that are exact or very similar to the site’s page.


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6World Wide Web

Computer Viruses

One last thought… Sources of data loss

• Virus- claims only 7% of lost data

• Hard Drive Failure- claims 44% of lost data

• Fire, Flood, etc- claims 10% of lost data

• Software Error- claims 14% of lost data

• Accidental Deletion- claims the other 21% of lost data

• Theft of PCPhysical access


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6World Wide Web

Censorship

Many pages on the Internet that generally would not be placed in the public library Bomb recipes Hacking software Pornography Racially and ethnically offensive material

In U.S., federal government in general has not tried to regulate Internet Free speech Regulate foreign sites China does have regulations on Internet sites

computer concepts 5th edition parsons/oja page 272 chapter 6 web technology section a parsons/oja...

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