computer concepts 5th edition parsons/oja page 272 chapter 6 web technology section a parsons/oja...
TRANSCRIPT
Computer Concepts 5th EditionParsons/Oja
Page 272
CHAPTER
6
Web TechnologySection A
PARSONS/OJA
Web Pages, Web Sites, And E-Commerce
Computer Concepts 5th EditionParsons/Oja
Page 273
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
Computer Concepts 5th EditionParsons/Oja
Page 273
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
Computer Concepts 5th EditionParsons/Oja
Page 280
Section AChapter
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…
Computer Concepts 5th EditionParsons/Oja
Page 281
Section AChapter
6Web Technology
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
Computer Concepts 5th EditionParsons/Oja
Page 281
Section AChapter
6Web Technology
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
Computer Concepts 5th EditionParsons/Oja
Page 281
Section AChapter
6Web Technology
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
Computer Concepts 5th EditionParsons/Oja
Page 281
Section AChapter
6Web Technology
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?
Computer Concepts 5th EditionParsons/Oja
Page 281
Section AChapter
6Web Technology
How do I know which players are installed?
Computer Concepts 5th EditionParsons/Oja
Page 283
Section AChapter
6Web Technology
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
Computer Concepts 5th EditionParsons/Oja
Page 283
Section AChapter
6Web Technology
What if a Web server can’t find the file that a browser requested?
Computer Concepts 5th EditionParsons/Oja
Page 284
Section AChapter
6Web Technology
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
Computer Concepts 5th EditionParsons/Oja
Page 285
Section AChapter
6Web Technology
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
Computer Concepts 5th EditionParsons/Oja
Page 285
Section AChapter
6Web Technology
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
Computer Concepts 5th EditionParsons/Oja
Page 285-286
Section AChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 286
Section AChapter
6Web Technology
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
Computer Concepts 5th EditionParsons/Oja
Page 286
Section AChapter
6Web Technology
Does my computer have to accept cookies?
Computer Concepts 5th EditionParsons/Oja
Page 286
Section AChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 287
Section AChapter
6Web Technology
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
Computer Concepts 5th EditionParsons/Oja
Page 287
Section AChapter
6Web Technology
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
Computer Concepts 5th EditionParsons/Oja
Page 287
Section AChapter
6Web Technology
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
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
6Privacy
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
Computer Concepts 5th EditionParsons/Oja
Page 291
Section BChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 291
Section BChapter
6Basic Web Page Authoring
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
Computer Concepts 5th EditionParsons/Oja
Page 291
Section BChapter
6Basic Web Page Authoring
What can I put on a Web page?
Computer Concepts 5th EditionParsons/Oja
Page 295
Section BChapter
6Basic Web Page Authoring
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
Computer Concepts 5th EditionParsons/Oja
Page 296
Section BChapter
6Basic Web Page Authoring
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
Computer Concepts 5th EditionParsons/Oja
Page 298-299
Section BChapter
6Basic Web Page Authoring
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
Computer Concepts 5th EditionParsons/Oja
Page 302
Section CChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 305
Section CChapter
6Web Page Extensions, Scripts, and Programs
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
Computer Concepts 5th EditionParsons/Oja
Page 305
Section CChapter
6Web Page Extensions, Scripts, and Programs
What is an ActiveX control?
Computer Concepts 5th EditionParsons/Oja
Page 306
Section CChapter
6Web Page Extensions, Scripts, and Programs
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
Computer Concepts 5th EditionParsons/Oja
Page 306
Section CChapter
6Web Page Extensions, Scripts, and Programs
Are ActiveX controls safe?
Computer Concepts 5th EditionParsons/Oja
Page 306
Section CChapter
6Web Page Extensions, Scripts, and Programs
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
Computer Concepts 5th EditionParsons/Oja
Page 307
Section CChapter
6Web Page Extensions, Scripts, and Programs
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
Computer Concepts 5th EditionParsons/Oja
Page 307
Section CChapter
6Web Page Extensions, Scripts, and Programs
How does a digital certificate work?
Computer Concepts 5th EditionParsons/Oja
Page 309
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 309
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 310
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 310
Section DChapter
6E-Commerce
How does e-commerce work?
Computer Concepts 5th EditionParsons/Oja
Page 310-311
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 311
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 311
Section DChapter
6E-Commerce
How do shopping carts work?
Computer Concepts 5th EditionParsons/Oja
Page 312
Section DChapter
6E-Commerce
What is an HTML form?
Computer Concepts 5th EditionParsons/Oja
Page 313
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 313
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 314-315
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 314-315
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 315
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 316-317
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
6E-Commerce
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
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
6World Wide Web
Online gambling
Currently not regulated Convenience Credibility of casino
Registered with Interactive Gaming Council?? Women???
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
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.
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
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
Computer Concepts 5th EditionParsons/Oja
Page 317
Section DChapter
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