The Web and E-mail

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5 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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Chapter 7

The Web and E
-
mail


2

The Web and E
-
mail

Contents



Web technology


Search engines


E
-
commerce


E
-
mail


Web and E
-
mail security



3

The Web and E
-
mail

CHAPTER OVERVIEW


Describe the roles that HTML, XHTML, HTTP,
URLs, browsers, and Web servers play in
bringing Web pages to your desktop


List the names of at least four Web browsers


Describe the purpose of helper applications,
plug
-
ins, and players


Describe the significance of a browser cache


4

The Web and E
-
mail


Explain why cookie are useful in an environment
that is based on a stateless protocol, and provide
some concrete examples of their use


Identify the elements that typically form a Web
page


Explain how to test and post Web pages


List some advantages and disadvantages of
HTML scripts


List and describe the elements of a search engine


CHAPTER OBJECTIVES



5

The Web and E
-
mail

CHAPTER OBJECTIVES


Demonstrate that you can use a search engine to
locate information on the Web


Create advanced search queries and correctly
format citations for Web
-
based materials


Discuss why e
-
commerce has become so popular
with consumers and merchants


List some threats to the security of credit card
numbers and other sensitive data during e
-
commerce transactions


6

The Web and E
-
mail

CHAPTER OBJECTIVES


Describe how the following e
-
commerce
technologies work: shopping carts, SSL, one
-
time
-
use credit cards, electronic wallets, and person
-
to
-
person payment systems


List the features that you would expect to find in a
typical e
-
mail software package


Explain how an e
-
mail system works and describe
the difference between POP and Web
-
based e
-
mail


List security precautions you can take to avoid
cookie exploits, pharming, spam, and phishing


7

The Web and E
-
mail

Web Technology

P288

Section A

In Section A, you’ll peel back the layers of Web
technologies to take a look at what happens
behind your browser window.


What is the Web

Web
(short for World Wide Web) is a collection of document,
image, video, and sound files that can be linked and accessed
over the Internet using a protocol called HTTP.


8

The Web and E
-
mail

WEB BASIC

P288
-
289


What is a Web site

A
Web site

typically contains a collection of related
information organized and formatted so it can be accessed
using software called a browser.


What is a 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.


When using a

browser
, you can access a Web page by
clicking a hypertext link or by typing a URL.


A URL is a type of URI(Uniform Resource Identifier),
such as
http://www.jxstnu.cn
.

Section A


9

The Web and E
-
mail

HTML

P290
-
291


What is HTML


HTML
(Hypertext Markup Language) is a set of
specifications for creating documents that a browser can
display as a Web page.


HTML tags
, such as <hr> and <b>, are incorporated into
an HTML document, which is similar to a word processing
file, but has an .htm or .html extension.


An HTML document contains text and HTML tags.
Formatting tags are used to change font size, separate
paragraphs, and add rules. Other tags add graphics and
links to a page. The HTML document produces a Web page.

Section A


10

The Web and E
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mail

HTTP

P292


How does HTTP work

HTTP

is a protocol that works with TCP/IP to get Web
resources to your desktop.

HTTP messages flow between a browser and a Web server.

Section A


11

The Web and E
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mail

HTTP

P293


Is each Web page element retrieved separately

Yes.
HTTP

is classified as a stateless protocol, and it
generally allows only one request and response per session.


What if an element cannot be found

When a broken link points to a nonexistent HTML
document, your browser typically produces a 404 Not Found
error.

When a broken link points to a nonexistent graphic or other
non
-
HTML file, your browser usually displays one of the
broken link icons.

Section A


12

The Web and E
-
mail

WEB BROWSERS

P293
-
294


What are some of today’s most popular browsers

Today’s most popular
browser
s include Microsoft Internet
Explorer, Mozilla Firefox, Apple Safari, Netscape Navigator, and
Opera.


Should I upgrade my browser when new versions become available

It is a good idea to upgrade when a new version of your browser
appears.


Why do I have to download software to view some Web page

Today, browsers work with additional file formats. Some
browsers do not have built
-
in support for proprietary file formats
commonly used on the Web to display video, animation, and other
media.

Section A


13

The Web and E
-
mail

WEB BROWSERS

P295


What is a helper application

A helper application is a program that extends a browser’s ability
to work with file formats.


Is a plug
-
in the same as a helper application

A plug
-
in is a type of helper application, pioneered by Netscape
developers, that can be activated form an <embed> tag inserted in
an HTML document.


What is a browser cache

When your browser fetches pages and graphics to from a Web
page, it stores that material on your computer in temporary files
sometimes referred to as a Web cache or browser catch.

Section A


14

The Web and E
-
mail

COOKIES

P296

Section A


What is a cookie

A
cookie

is a small chunk of data generated by a Web server and
stored in a text file on your computer’s hard disk.


15

The Web and E
-
mail

WEB PAGE AUTHORING

P297
-
299


What tools can I use to create Web pages


You can create Web pages by tools such as Microsoft FrontPage,
Dreamweaver, Firework etc.


Creating a Web page is not the end of the publishing process.
You also must test your pages, transfer them to a Web server, and
test all your links.


HTML
script
s(
脚本
)


A series of program instructions called an
HTML script

can be
embedded directly into the text of an HTML document. Scripts
instruct the browser to perform specific actions or respond to
specific user actions.

Section A


16

The Web and E
-
mail

HTML SCRIPTS

P299
-
301


HTML
script
s(
脚本
)


HTML forms
(
表单
⤠慲攠瑹灩捡汬c⁵獥搠瑯 捯汬散琠灡pm敮琠慮a
shipping information at the checkout counter of e
-
commerce Web
sites.


Scripts can run on a client or a server.


A Java applet is an application written in the Java programming
language.


An ActiveX control is a compiled computer program that can be
referenced from within an HTML document, downloaded,
installed on your computer, and executed within the browser.


Scripts are somewhat more difficult to write and test than
HTML documents.

Section A


17

The Web and E
-
mail

Search Engines

P302
-
303

Section B

In Section B, you’ll find out how Web search
engines work, so that you can use them more
efficiently.


What is a Web search engine


A Web search engine

is a program designed to help people
locate information on the Web by formulating simple
keyword queries.


Search engine sites often contain a variety of tools and
services in addition to search engine access.


A search engine contains four components
: a
Web crawler

(
网络蜘蛛
⤬)慮a
楮摥硩湧n畴楬楴y
(
索引器
⤬)愠摡瑡扡獥Ⱐ慮搠愠
query processor.


18

The Web and E
-
mail

SEARCH ENGINE BASICS

p303
-
304


A Web crawler

is a computer program that is automated
to
methodically
(
有系统地
⤠癩獩琠W敢⁳e瑥t.


A Web crawler begins with a list of URLs to visit. After
copying the material at a specified URL, the Web crawler
looks for hypertext links and adds them to the list of URLs
to visit.


The number of times a search engine’s crawler visits a
Web page varies, depending on several factors such as how
often the page tends to change and its popularity.


A
search engine indexer

is software that pulls keywords
from a Web page and stores them in a database. The
purpose of it is to make pages easy to find based on their
contents.

Section B


19

The Web and E
-
mail

FORMULATING SEARCHES

p306
-
307

Section B


How can I formulate a basic search

When
formulating
(
明确叙述

煵敲楥

查询
⤬)k敥瀠瑨攠
following guidelines:


20

The Web and E
-
mail

FORMULATING SEARCHES

p307
-
308


What are
Boolean operators
(
逻辑算子
)

A
Boolean operator

is a word or symbol that describes a
relationship between keywords and thereby helps you create
a more
focuse
d(
聚焦
⤠煵敲q.

Section B


21

The Web and E
-
mail

FORMULATING SEARCHES

p308
-
309


What is an
advanced search
(
高级搜索
)

In an advanced search, you might provide more than one
queries to make your searches more precise and obtain more
useful results.


What kind of information does a search engine store

In addition to storing an ID number, search engines store
the IP address from which the query was initiated, the data
and time of the query, the search terms, and the URL for the
Web site linked to from the results list.

Section B


22

The Web and E
-
mail

CITING WEB
-
BASED SOURCE MATERIAL

p310
-
311


You can copy text and graphics that you find on Web
pages.


When compiling the
citation
(
引用
⤠景f湬 湥n獯畲捥cⰠ浡,攠
獵s攠祯甠灲潶楤攠
獵晦楣i敮e
(
足够
⤠楮i潲o慴a潮o瑯⁡t汯l
r敡摥牳⁴漠汯e慴a 祯畲⁳潵 捥c


When you use
material
(
材料
⤬)獯s整e浥猠祯甠湥敤n
灥牭楳i楯i
(
许可



To
obtain
(
获得
⤠灥牭楳i楯渠瑯⁵獥⁴ 硴Ⱐx桯瑯猬畳楣Ⱐ
癩摥潳Ⱐ慮搠潴桥o⁥汥浥湴猠祯甠晩湤n⁴桥 W敢Ⱐ捯湴慣琠瑨攠
捯灹物杨c 桯汤敲 批be
-
浡m氬l數灬慩渠w桡琠祯甠y慮琠瑯⁵獥
慮搠桯h 祯甠灬慮⁴漠p獥s楴.

Section B


23

The Web and E
-
mail

E
-
commerce
P312

Section C

Section C focuses on e
-
commerce and the
technologies a typical shopper might encounter
on the Web.


What is e
-
commerce


E
-
commerce

refers to business
transaction
s(
交易
⤠瑨慴⁡t攠
conducted electronically over a computer network.


It
encompass
es(
包括
⤠慬a
慳灥捴

方面
⤠潦⁢畳楮敳u 慮搠
浡mk整e湧n灲潣敳o敳e敮慢汥搠批⁉湴敲湥琠n湤nW敢e
technologies.


24

The Web and E
-
mail

E
-
COMMERCE BASICS
P312


Many e
-
commerce activities are classified as B2C
(business
-
to
-
consumer) in which individual consumers
purchase
(
购买
⤠杯潤猠慮a 獥牶楣敳e晲潭湬楮攠浥m捨慮瑳t


C2C(consumer
-
to
-
consumer) is another popular e
-
commerce model, in which consumers sell to each other at
popular online auctions.


E
-
commerce enhances traditional business models by
offering efficiency and opportunities for
automation
(
自动操

⤬)
捯c灵瑥物z慴a潮
(
计算机化
⤬)慮搠
摩杩瑩z慴a潮
(
数字化
⤮)


Both merchants and consumers benefit from e
-
commerce
because
niche goods
(
利基产品
⤠慮a 獭慬s 浥m捨慮瑳⁣慮
reach a global customer base.

Section C


25

The Web and E
-
mail

ONLINE SHOPPING
P314
-
315



E
-
commerce offers some unique advantages over brick
-
and
-
mortar stores and mail
-
order catalogs. Customers can easily
search for specific merchandise, and can easily compare prices
between multiple
vendor
s(
卖主
⤠畳楮朠W敢⁳e瑥t⸠


Online

shopping

cart

is

a

cyberspace

version

of

the

metal
(


)

捡牴

祯u

睨敥e

慲潵湤

a

獴ore

慮a

晩汬


(
装满
)

w楴h

浥r捨慮摩獥
(
商品
)
.



Most

shopping

carts

work

because

they

use

cookies

to

store

information

about

your

activities

on

a

Web

site
.


Section C


26

The Web and E
-
mail

ONLINE AUCYIONS

P316

Section C


An
online auction
(
在线拍卖
⤠楳⁴桥⁥汥捴c潮楣 敱畩癡e敮琠瑯e
杯潤汤
-
晡f桩潮敤⁹慲搠獡h敳Ⱐ
牵浭慧攠獡汥s
(
清仓拍卖
⤬)慮搠
auctions .


You

can

expect

to

bid
(
叫牌
)



湥w,

畳敤u

捬潳敯畴
(
出清存货


潶敲獴o捫
(
库存过剩




r敦畲扩獨
敤e
刷新
)

楴e浳





潮汩ne

auction
.


eBay

is

by

far

the

largest

and

most

popular

auction

site

.


27

The Web and E
-
mail

ONLINE PAYMENT

P317
-
318

Section C


The

most

popular

ways

to

make

online

payments

include

submit
ting(
提交
)

祯畲

捲敤楴

捡牤

湵浢敲

摩d e 捴c y



a

merchant

and

using

a

third
-
party

payment

service
.


To

protect

your

credit

card

from

packet

sniffers,

you

should

engage

in

electronic

transactions

only

over

a

secure

connection
.


SSL(Secure

Sockets

Layer)

and

its

successor
(
后续的事物
)

呌匨S牡湳灯牴

䱡祥L

卥捵物S礩

慲e

灲潴潣潬o

瑨慴

敮捲祰e

摡瑡

瑲t癥汩湧

扥瑷敥e

a

捬c敮e

捯c灵瑥p

慮a



䡔呐

獥牶sr
.


S
-
HTTP(Secure

HTTP)

is

an

extension

of

HTTP

that

simply

encrypt
s(
加密
)

瑨t

瑥tt





䡔呐

浥獳慧s

扥景be





獥湴
.


28

The Web and E
-
mail

ONLINE PAYMENT

P318
-
319

Section C


A person
-
to
-
person payment(P2P payment) offers an
alternative to credit cards.


Can’t

misuse

it

or

store

it

on

an

unsecured

computer
.


A

one
-
time
-
use

credit

card

allows

consumers

to

make

purchases

while

keeping

their

actual

card

numbers

hidden
.



An

electronic

wallet
(
电子钱夹
)



s潦ow慲e

瑨tt

獴潲敳

扩汬楮i

慮a

s桩灰楮h

楮i潲浡瑩潮o

睨楣i

捡c



獵扭s瑴敤

睨en

晩湡汩z楮i



e
-
捯c浥r捥

灵p捨慳c
.


29

The Web and E
-
mail

E

浡楬

P320

Section D

In this section, you get some background
information about how e
-
mail works, the
difference between Web
-
based e
-
mail and
traditional client
-
based e
-
mail.


Who can use e
-
mail

Any person with an e
-
mail account can send and receive e
-
mail.

An e
-
mail account provides access to a storage area, or
mailbox, supplied by an e
-
mail provider.


30

The Web and E
-
mail

E
-
MAIL OVERVIEW

P320
-
321


Exactly what is an e
-
mail message

An e
-
mail message is a document that is composed on a
computer and remains in digital, or electronic, from so that
it can be transmitted to another computer.

A message header includes the recipient’s e
-
mail address
and message subject.


What can I do with basic e
-
mail

Basic e
-
mail activities consist of writing, reading, replying to,
and forwarding messages.

Section D


31

The Web and E
-
mail

E
-
MAIL OVERVIEW

P321
-
323

Section D


How does forwarding work

After you receive an e
-
mail message, you can use the
Forward
(
转寄
⤠)敡e畲攠瑯⁰慳猠楴 楮⁴漠潴桥o⁰敯灬攮


What’s an e
-
mail attachment

Any file that travels with an e
-
mail message is called an e
-
mail
attachment
(
附件



How does HTML relate to e
-
mail

An e
-
mail message in HTML format can include graphics in
addition to a variety of fonts and font colors.


32

The Web and E
-
mail

E
-
MAIL OVERVIEW

P323

Section D


What other e
-
mail features are available


33

The Web and E
-
mail

NETIQUETTE

P324


Is e
-
mail different from other types of communication

By understanding
netiquette
(
网络礼节
⤬)祯甠捡渠慶潩搠獯y攠
潦⁴桥h
灩p晡f汳
(
缺陷
⤠慮搠灲潢汥o猠潦⁥
-
浡m氠捯c浵湩m慴a潮献

Netiquette is online
jargon
(
行话
⤠景f⁉湴敲湥琠
整e煵整ee
(
礼节


Section D


34

The Web and E
-
mail

E
-
MAIL TECHNOLOGY

p325


What is an e
-
mail system

An
e
-
mail system

is the equipment and software that carries
and manipulates e
-
mail messages.

It includes
computers
and
software called e
-
mail servers

that
sort
(
分类
⤬)獴潲攬e慮搠
r潵瑥
(
发送
⤠浡m氮

E
-
浡m氠楳⁢慳敤a潮o
獴潲e
-
慮a
-
景fw慲搠瑥t桮潬潧h
ⴭⴭ

捯c浵湩m慴a潮猠浥瑨潤⁩渠w桩捨h摡瑡⁴桡琠捡湮潴⁢攠h敮琠
摩d散e汹l瑯⁩瑳t摥獴楮慴楯渠楳⁴敭灯牡物p礠獴潲敤⁵湴楬
瑲t湳浩獳s潮o楳⁰潳獩扬攮


Section D


35

The Web and E
-
mail

E
-
MAIL TECHNOLOGY

p325

Section D


What is an e
-
mail system

Three types of e
-
mail systems are widely used today:

POP
,
IMAP
, and
Web
-
based mail
.


POP(Post Office Protocol)

temporarily stores new
messages on an e
-
mail serve. When you connect to your ISP
and request your mail, it s downloaded from the e
-
mail
server and stored on your computer.


IMAP(Internet Messaging Access Protocol)

is similar to
POP, except that you have the option of downloading your
mail or leaving it on the server.


Web
-
based e
-
mail

keeps your mail at a Web site, where it
can be accessed using a standard Web browser.


36

The Web and E
-
mail

E
-
MAIL TECHNOLOGY

p326


How do I use Web
-
based e
-
mail

First you need an e
-
mail account with a Web
-
based e
-
mail
provider. Then at the Web site, you can write, read, reply to,
and delete e
-
mail messages.


How do POP and IMAP work

Section D


37

The Web and E
-
mail

E
-
MAIL TECHNOLOGY

p327


Does e
-
mail client software work only for offline e
-
mail tasks

No.


How does POP mail compare to Web
-
based e
-
mail


Similar: allowing you to read, compose, reply to, delete, and
forward e
-
mail messages; maintain an address book; and send
attachments.


Dissimilar


POP mail requires you to install and use e
-
mail client software,
whereas Web
-
based e
-
mail allows you to use a browser to work
with your mail.


POP transfers messages to your computer’s hard disk, whereas
a Web
-
based e
-
mail system retains your messages on its server.

Section D


38

The Web and E
-
mail

Web and E
-
mail Security

P328

In this section, you’ll learn about specific spam
and spyware exploits and find out how to
minimize the risk they pose to computer security
and your privacy.


Can cookies be a security risk

Yes.

Section E


What is an ad
-
serving cookie

An ad
-
serving cookie is created by a third party ad, and is
used to track your Internet activities across sites.


39

The Web and E
-
mail

COOKIE EXPLOITS

P329

Section E


Can I turn off cookies to foil ad
-
serving exploits

Most browsers offer a way to turn off third
-
party cookies.


Does deleting cookies reduce risk

By deleting cookies, you can still interact with online
shopping carts and take part in other activities that require
cookies, but deleted third
-
party cookies won’t be able to
communicate with their handlers.


40

The Web and E
-
mail

COOKIE EXPLOITS

P330

331


A Flash Cookie

A
Flash cookie
(local shared object) is the Flash equivalent of a
conventional Web cookie.

You can manually delete Flash cookies from your computer, or
visit the Adobe Flash Player Web site to adjust your computer’s
settings for Flash cookies.


A Web bug

A
Web bug

or clear GIF is typically a 1x1 pixel graphic embedded
in a Web page or e
-
mail message.

Antispyware

can avoid responding to or downloading spyware
from pop
-
up ads.

Individuals who prefer not to leave a
trail
(
踪迹
⤠潦⁴ 敩e⁉湴敲湥琠
慣瑩a楴楥猠
獵牦
(
冲浪
⤠瑨r潵杨⁡渠
慮潮祭y畳
(
匿名的

灲潸礠
獥s癥v
(
代理服务器
⤠睨楣栠r敬慹猠祯畲 W敢⁰e来⁲敱略獴猠慦e敲
獴物灰楮朠潦f
(
剥离
⤠祯畲 䥐⁡摤d敳e.

Section E


41

The Web and E
-
mail

FAKE SITES

P331

332

Section E


A fake site

A
fake Web site
looks
legitimate
(
合法
⤬)扵琠桡猠扥敮⁣h敡e敤e
by a third party to be a very clever
replica
(
复制品
⤠潦⁡o
legitimate Web site.

Pharming

is an exploit that
redirect
s(
使改变方向
⤠畳敲u⁴漠
fake site by “poisoning” a domain name server with a false
IP address.

To detect a possible pharming attack, you can use anti
-
pharming tools.

参考网页

http://www.anti
-
spam.org.cn/AID/742


42

The Web and E
-
mail

SPAM

P333

Section E


spam

Spam
(
兜售信息
⤠楳⁵湷慮瑥搠
敬e捴c潮楣o橵湫慩l
(
电子邮寄宣
传品
⤠慢潵琠浥摩捡d 灲潤畣瑳Ⱐ汯l
-
捯獴潡湳Ⱐ慮搠晡f攠
software upgrades that arrives in your online mailbox.

In the past, spam
flooding
(
泛滥
⤠祯畲⁉湢潸 w楴栠
畮獯汩捩c敤
(
主动提供
⤠慮搠潦o敮e
灯牮潧牡灨楣
(
色情
⤠浥獳慧敳
was merely an
annoyance
(
烦恼


These days, spam has turned into another major hacking
tool for
cyber criminals
(
网络犯罪


A 獰慭s
晩汴敲
(
过滤器
⤠楳⁡⁴祰攠潦⁵o楬楴礠獯s瑷慲攠瑨慴
捡灴畲敳⁵湳潬楣i瑥搠e
-
浡m氠浥獳慧敳 扥景b攠瑨敹⁲敡捨e祯畲
䥮扯砮


43

The Web and E
-
mail

SPAM

P334

Section E

Guidelines for Avoiding Spam.

To
combat
(
抗击
⤠獰慭⁳敮琠批e
桩h慣a敤
(
抢劫
⤠扯瑮整
computers, e
-
mail
authentication
(
鉴定
⤠瑥捨湩煵敳t
癥物vy
(


) that e
-
mail messages originate form the Internet domain
from which they claim to have been sent.


44

The Web and E
-
mail

PHISHING

P334
-
335


What is phishing

Phishing
(
钓鱼攻击
⤠楳i慮⁥
-
mail based scam that’s designed to
persuade you to
reveal
(
暴露
⤠捯湦楤敮瑩慬 楮景牭慴楯渮

Be suspicious of e
-
mail messages that supposedly come from
banks, ISPs, online payment services, OS publishers, and online
merchants.

The best defense against all the bad stuff on the Web and in e
-
mail:

Section E


45

The Web and E
-
mail

Do you have made a
progress today ?