The Web and Chapter 7

7 Chapter 7: The Web and 2 Chapter Contents  Section A: Web Technology  Section B: Search Engines  Section C: E-commerce  Section D:  Section E: Web and Security

7 SECTION A Chapter 7: The Web and 3 Web Technology  Web Basics  HTML  HTTP  Web Browsers  Cookies  Web Page Authoring  HTML Scripts

7 Chapter 7: The Web and 4 Web Basics  The Web is an interlinked collection of document, image, video, and sound files  A Web site contains a collection of related information  Podcasts  RSS vs. Atom  Videocasting

7 Chapter 7: The Web and 5 Web Basics Web page  A Web page is the product or output of one or more Web-based files displayed in a format similar to a page in a book Web browserclient software  A Web browser is client software that displays Web page elements and handles links between pages URL  Every Web page has a unique address called a URL

7 Chapter 7: The Web and 6 HTML  Set of specifications for creating documents that a browser can display as a Web page  Markup language  HTML tags  XHTML – Extensible HTML  DHTML – Dynamic HTML  Ajax – Asynchronous JavaScript and XML

7 Chapter 7: The Web and 7 HTML UTA ExampleExample

7 Chapter 7: The Web and 8 HTTP HTTP messages flow between a browser and a Web server.

7 Chapter 7: The Web and 9 Web Browsers  Help you access Web pages  Upgrade to new browser versions as they become available  Popular browsers: –Internet Explorer –Mozilla Firefox –Apple Safari –Netscape Navigator –Opera

7 Chapter 7: The Web and 10 Web Browsers  Helper applications extend browser’s ability to work with file formats –A plug-in is a type of helper application –A player is any helper application or plug-in that helps a browser display a particular file format

7 Chapter 7: The Web and 11 Cookies  Small chunk of data generated by a Web server and stored on computer’s hard disk –Fix problems caused by HTTP’s stateless protocol –Relatively safe  Your computer does not have to accept cookies

7 Chapter 7: The Web and 12 Web Page Authoring  Text editor  HTML conversion tool  Online Web authoring tools  Web authoring software –Microsoft FrontPage –Adobe Dreamweaver

7 Chapter 7: The Web and 13 HTML Scripts  HTML scripts can perform complicated tasks and respond to user actions –HTML forms –Server-side script –Client-side script –Java applet –ActiveX control  Digital Certificate

7 SECTION B Chapter 7: The Web and 14 Search Engines  Search Engine Basics  Formulating Searches  Citing Web-based Source Material

7 Chapter 7: The Web and 15 Search Engine Basics  A Web search engine is a program designed to help people locate information on the Web by formulating simple keyword queries

7 Chapter 7: The Web and 16 Search Engine Basics Web crawler  A Web crawler is a computer program that is automated to methodically visit Web sites indexer  A search engine indexer is software that culls keywords from a Web page and stores them in a database query processor  A search engine’s query processor looks for your search terms in search engine’s indexed database and returns list of relevant Web sites  Link popularity is measured by quantity and quality of links from one Web page to others meta keyword  A meta keyword is entered into a header section of a Web page when it is created and is supposed to describe the page contents –Keyword stuffing

7 Chapter 7: The Web and 17 Formulating Searches  Most search engines work with keyword queries in which you enter one or more words, called search terms

7 Chapter 7: The Web and 18 Formulating Searches  A Boolean operator is a word or symbol that describes a relationship between keywords, helping you create a more focused query

7 Chapter 7: The Web and 19 Citing Web-Based Source To copy a passage of text from a Web page, highlight the text, click the Edit menu, then select Copy. Next, switch to your own document and use the Paste option.

7 Chapter 7: The Web and 20 Citing Web-Based Source

7 SECTION C Chapter 7: The Web and 21 E-commerce  E-commerce Basics  Online Shopping  Online Auctions  Online Payment

7 Chapter 7: The Web and 22 E-commerce Basics  Business transactions  Business transactions conducted electronically over a computer network –B2C (business-to-consumer) –C2C (consumer-to-consumer) –B2B (business-to-business) –B2G (business-to-government)

7 Chapter 7: The Web and 23 E-commerce Basics  Enhances traditional business models  Styles of online advertisements –Banner ad –Hover ad –Pop-up ad Click-through rate  Ad-blocking software prevents ads from appearing on screens

7 Chapter 7: The Web and 24 Online Shopping Transactions In a typical shopping session, you connect to storefront an online storefront and use navigation controls to browse through the catalog merchant’s catalog. As you browse, you can drop items into your electronic shopping cart electronic shopping cart. At the checkout counter, you enter the information pay necessary to pay for the items you selected.

7 Chapter 7: The Web and 25 Online Shopping

7 Chapter 7: The Web and 26 Shopping Carts

7 Chapter 7: The Web and 27 Online Auctions  An online auction is the electronic equivalent to good old-fashioned yard sales, rummage sales, and auctions  You can expect to bid on new, used, closeout, overstock, or refurbished items at an online auction  Computer software takes the place of an auctioneer

7 Chapter 7: The Web and 28 Online Payment  The most popular ways to make online payments include submitting your credit card number directly to a merchant and using a third-party payment service such as PayPal credit card numbers hijacked and used inappropriately  Online shoppers are justifiably worried that personal information and credit card numbers supplied in the course of an e-commerce transaction might be hijacked and used inappropriately

7 Chapter 7: The Web and 29 Online Payment  A secure connection encrypts the data transmitted between your computer and a Web site SSL (Secure Sockets Layer) S-HTTP (secure HTTP)

7 Chapter 7: The Web and 30 Online Payment  Person-to-person payments are an alternative to credit cards –The payment service is the only entity that sees your credit card number –Service is in its infancy  An electronic wallet is software that stores billing and shipping information

7 Chapter 7: The Web and 31 Online Payment An electronic wallet can transfer your billing and shipping information to a participating site’s e-commerce Web server when you check out.

7 SECTION D Chapter 7: The Web and 32 Web Technology (bonus)  The Internet Protocol Stack  Application Ports

7 Chapter 7: The Web and 33 Internet Protocol Stack standard  Nodes attached to the Internet implement a standard set of capabilities to allow communications between dissimilar systems across dissimilar communications links layeredmodularity ease of implementation  The standard protocol “stack” is implemented in a layered design to support modularity and ease of implementation in many different environments.

7 Chapter 7: The Web and 34 Internet Protocol Stack system software program  Think of each layer as a different system software program that runs on your computer. upper layers like applications  The upper layers allow like applications to communicate lower layers like devices  The lower layers allow like devices to communicate application transport network link physical APPLICATION CATEGORY DEPENDENT OPERATING SYSTEM CONTROLLED NETWORKE HARDWARE DEPENDENT HTTP, etc. TCP or UDP IP Ethernet UTP, fiber, etc.

7 Chapter 7: The Web and 35 Internet Protocol Stack application transport network link physical application transport network link physical Your Client Application Target Server Application Your Messages packets The Internet Web browser, client, etc. Web server, server, etc.

7 Chapter 7: The Web and 36 Internet Ports transport network link physical physical  The means by which a single physical node differentiates multiple requests, like , web, file transfer, etc. transport  The transport layer passes requests to specific “ports” into the application layer File Transfer Application Application Web Server Application

7 SECTION D Chapter 7: The Web and 37  Overview  Netiquette  Technology

7 Chapter 7: The Web and 38 Overview  Any person with an account can send and receive messages

7 Chapter 7: The Web and 39 Overview  Basic activities –Writing –Reading –Replying –Forwarding

7 Chapter 7: The Web and 40 Overview  attachments are files that travel with an message – software converts attachments to MIME  HTML-compliant software  Additional features

7 Chapter 7: The Web and 41 Overview

7 Chapter 7: The Web and 42 Netiquette  Internet etiquette –Meaningful subject –Use uppercase and lowercase letters –Check spelling –Be careful what you send –Be polite –Be cautious with sarcasm and humor

7 Chapter 7: The Web and 43 Netiquette –Use smileys and text messaging shorthand cautiously –Use the Bcc function for group mailings –Don’t send replies to all recipients –Don’t send huge attachments –Explain attachments –Stay alert for viruses –Notify recipients of viruses

7 Chapter 7: The Web and 44 Technology  systems carry and manipulate messages – servers store-and-forward –Based on store-and-forward technology (SMTP)  Three types of client systems widely used today: –POP –IMAP –Web-based

7 Chapter 7: The Web and 45 Technology POP server  A POP server is a computer that stores your incoming messages until they can be transferred to your hard disk – client software SMTP server  An SMTP server is a server that forwards s that you send

7 Chapter 7: The Web and 46 1) Alice uses an client program to compose a message and “to” 2) Alice’s mail client sends the message to her mail server where it is placed in a message queue (SMTP) 3) Client side of opens a “connection” with Bob’s mail server 4) The client-side mail server sends Alice’s message over the connection (SMTP) 5) Bob’s mail server places the message in Bob’s mailbox on the server 6) Bob opens his client program to download and read Alice’s message (POP3) user agent mail server mail server user agent Technology: SMTP mail Slide from Computer Networks: A Tops-Down Approach, Kurose and Ross

7 Chapter 7: The Web and 47 Technology: Web mail  Web-based accounts allow you to use a browser to access your messages  Messages are sent as form data between the client and the server using HTTP (not SMTP/POP).  Your Web server re-formats and then forwards your using SMTP. Web Client Mail SMTP mail server user agent Web HTTP 4 3 SMTP

7 SECTION E Chapter 7: The Web and 48 Web and Security  Cookie Exploits  Fake Sites  Spam  Phishing

7 Chapter 7: The Web and 49 Cookie Exploits ad-serving cookie  An ad-serving cookie can track your activities at any site containing banner ads from a third party

7 Chapter 7: The Web and 50 Cookie Exploits  A Flash cookie, also called a local shared object, is the Flash equivalent of a conventional Web cookie  A Web bug or clear GIF is typically a 1x1 pixel graphic embedded in a Web page or message. It is almost invisible due to its size, and is designed to track who’s reading the Web page or message  Antispyware is a type of security software designed to identify and neutralize Web bugs, ad-serving cookies, and other spyware

7 Chapter 7: The Web and 51 Cookie Exploits  Individuals who prefer not to leave a trail of their Internet activities surf through an anonymous proxy service, which uses an intermediary, or proxy, server to relay Web page requests after masking the originating IP address

7 Chapter 7: The Web and 52 Fake Sites fake Web site  A fake Web site looks legitimate, but has been created by a third party to be a very clever replica of a legitimate Web site  Pharming  Pharming is an exploit that redirects users to fake sites by “poisoning” a domain name server with a false IP address

7 Chapter 7: The Web and 53 Spam unwanted electronic junk mail  Spam is unwanted electronic junk mail about medical products, low-cost loans, and fake software upgrades that arrives in your online mailbox spam filter  A spam filter is a type of utility software that captures unsolicited messages before they reach your inbox –Local filtering –ISP filtering

7 Chapter 7: The Web and 54 Spam

7 Chapter 7: The Web and 55 Phishing based scam  Phishing is an based scam designed to persuade you to reveal confidential information, such as your bank account number or Social Security number  If you don’t want to become a phishing victim, be suspicious of messages that supposedly come from banks, ISPs, online payment services, operating system publishers, and online merchants

7 Chapter 7: The Web and 56 Phishing

Chapter 7 Complete The Web and