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Internet applications – Internet Serivces
4. Internet Services and Resources
The Internet provides various services and resources. In this section, we shall discuss how to find what you need, the major Internet applications and ways you can use the Internet to communicate with people, including e-mail, newsgroup, etc…4.1 World Wide Web
The World Wide Web ( ) is a collection of electronic files among web servers on the Internet. By establishing a linked relationship between Web documents, related information becomes easily accessible.4.1.14.1.1 Hypertext Transfer ProtocolHypertext Transfer Protocol ( ( ))The primary function of HTTP is to establish a connection with a Web __________ and transmit ____________ pages or any other files to the Web _____________.
4.1.24.1.2 Hypertext Markup Language (HTML)Hypertext Markup Language (HTML)Web documents are created using HTML which is a ____________________, or tags, which is used to create ________________. HTML tells the Web browser how to display the text contained in the Web pages. Web pages can be created by using a text editor (e.g. ___________ ). However, there are a number of user-friendly web authoring software, such as Dreamweaver, that allow you to generate HTML documents. The tags are inserted automatically for you in the web authoring software.
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TCP connectionIP packets
Web Browser
Web Server(HTTP server)
1. HTTP Request
2. HTML page
Web browsers communicate with Web servers via the TCP/IP protocol. The browser sends HTTP requests to the server, which responds by sending back messages and HTML pages.
Over the last decade, billions of Web pages have been created with HTML. Now, however, the World Wide Web Consortium has posted a more feature-rich standard – XHTML. HTML and XHTML are both widely accepted and used by Web developers.
Exercise4.1 Use a text editor (Notepad) to create the following HTML document and save it as “p1.htm”.
Use a web browser to browse it.<HTML><HEAD><TITLE>My First Web Page</TITLE></HEAD><BODY BGCOLOR=”YELLOW”><CENTER>Page One</CENTER></BODY></HTML>
4.2 Use a web authoring software (Dreamweaver) to create a HTML document with a green background and a text “Page Two” at the center. Save the document as “p2.htm”. Use a web browser to browse it.
4.3 Download a photo from our school web site and name it as “photo.jpg”. Create the following HTML document and save it as “p3.htm”. Use a web browser to browse it.<BODY><IMG SRC=”photo.jpg”></BODY>
4.1.34.1.3 HyperlinkHyperlinkIn order to link Web pages to each other on the Internet, hyperlinks are used. Hyperlinks are instructions that point to other HTML documents, to another section of the same document (i.e. Bookmark) or to other multimedia elements on the Web.
Exercise4.4 Create a file with content “It is a word document.” with WORD and save as “note.doc”.
Create the following HTML document and save as “main.htm”.<BODY><P><A HREF=”p1.htm”>Link to page 1</A><p><A HREF=”p3.htm”>Link to photo</A><p><A HREF=”note.doc”>Download a file</A><p><A HREF=”http://ychlpyss.edu.hk”>Link to LPY</A><p><A HREF=”mailto:[email protected]”>Email to me</A>
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Internet applications – Internet Serivces
</BODY>
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4.1.44.1.4 Searching for Information on the InternetSearching for Information on the InternetBasic strategic on searchingBasically, there are two ways to search information on Internet by web browser. They are search engines and web directories.
There are different web search strategies that help users to find information. A search engine is a software program that finds web sites and web pages. There are thousands of search engines exist. Some search on any topic and others are restricted to certain subjects, such as finding people or job hunting.
Popular search enginesSearch Engine Web addressAltaVista http://www.altavista.comExcite http://www.excite.comGoogle http://www.google.comMSN Internet Search http://microsoft.msn.comYahoo http://www.yahoo.com
Effective Search TechniquesTo find information on the Internet efficiently, you had better read the search rules first because each search engine has different rules for formulating the inquiry. Besides, you can get results with more than one search engine. The results vary significantly between search engines, because their databases are compiled in completely different manners.
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Different results of the search contained from Yahoo and Google
Internet applications – Internet Serivces
1. By keywords or phasesIt is the most widely used search method. The keywords and phrases you enter are critical to the success of your search. Choose them carefully and try to be as specific as you can.
o Search Operator: You can use search operators in search expression. They are AND, OR and NOT.
Search Operators Example ExplanationAND China AND Canada Find results with both China AND Canada
OR China OR Canada Find results with China OR Canada
NOT China NOT Canada Find results with China except Canada
o Wildcard Character: You can also use wildcard characters. Most search engines support these wildcard characters in their search expressions. A wildcard character allows you to omit part of a search term. Many search engines recognize the asterisk (*) as the wildcard character. For example, the search expression “wom*n” would return pages containing both woman and women.
o Advanced Search: Many search engines have “Advanced Search” feature, which offers numerous options for making your searches more precise and getting more useful results. Users can search the results of web pages which are written in a certain language, created in a certain file format, that have been updated within a certain period of time, etc… See the following figure.
Exercise4.5 Use Yahoo and Google to search for our school’s web site address and compare the
differences.4.6 What is the procedure to suggest a web site to the search engine?
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2. Web directory Web directories use a completely different approach from search engines to build useful indexed of information on the Web. It is a listing of hyperlinks to Web pages that is organized into different categories. Users can click an appropriate category to find the information you want.
There is plenty of useful and good quality information on the Internet. However, users may enter some harmful web sites and see some incorrect or indecent information by mistake carelessly. For example, methods of committing suicide had sometimes been introduced on web sites and sexual web-sites are plenty in the Internet. Besides choose carefully, we may avoid enter those web sites erroneously by screening them out using filtering software. In order to read only correct and good information on the Internet, we need to choose carefully and seek help from teachers when necessary.
4.1.5 File Transfer Protocol (FTP)
The File Transfer Protocol (FTP) allows users to download and upload files on the Internet. An FTP server is a computer that allows users to upload and download files using FTP. An FTP site contains electronic files including text, graphics, audio clips, video clips and program files that reside on an FTP server.
You must have an authorized account (username and password) in order to access the FTP sites. Many FTP sites have anonymous FTP, i.e. anyone on the Internet can transfer files without prior permission.
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Internet applications – Internet Serivces
Using a Browser to Access FTP Site
FTP Client ProgramUsers can download file using an FTP client program, such as WS_FTP LE program.
Exercise4.7 Use a FTP client software to connect to your account and upload your files in 4.1-4.4. Test
the web pages on the Internet.
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In the Microsoft Internet Explorer, type the Web address of FTP site
Click the “New” button in the Session Properties dialog box. Some ftp site allow anonymous logon.
FTP site address
Anonymous login selected
Type your e-mail address
Winzip files
Download button
Upload button
Toolbar
Message Area
4.2 Electronic Email (E-mail)
E-mail is a common communications method in our society. Users can send and receive e-mail with anyone who has an e-mail address. We can use ______________ or ______________ to send or receive e-mail. The former one, such as Microsoft Outlook, enables e-mail though a program running on your computer. Web-based email is handled through interaction with a web site, such as Yahoo!
The advantages of using e-mail client program are that e-mail can be integrated with other applications such as a ________________ and _____________. Besides, it can __________ or ______________ e-mail message by sender, so that it provides better security level over using the Web-based e-mail approach. For the Web-based e-mail, it is ____________________ from any Internet-connected computer in the world.
4.4.22.1..1. Email AddressEmail AddressAn e-mail address is a combination of a user name and a domain name that identifies a user so he or she can receive Internet e-mail. An @ (pronounced at) symbol separates the user name from the domain name.
The followings are several commonly used protocols for sending or receiving email.Simple Mail Transfer Protocol (SMTP)SMTP decides which paths an e-mail message takes on the Internet. It handles outgoing message.Post Office Protocol (POP)POP handles incoming messages. POP3 is the latest version of POP, which provides a message store that holds incoming e-mail until users log on and download it.Other protocolsInternet Message Access Protocol (IMAP): IMAP is another protocol for retrieving mail message from a server.Multipurpose Internet Mail Extensions (MIME): MIME specifics how to encode non-text data, such as graphics and sound, so it can travel over the Internet.Exercise4.8 Use a web-based email to send a mail to [email protected] with an attachment of a word
document (the document content is : "Hello! Have a nice day!"), cc to yourself and bcc to [email protected]. The content of the mail is your name and class.
4.9 Use Outlook Express to mock a sender with address ([email protected]) and send a mail to [email protected]. The content of the mail is your name and class.
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Username Domain Name
Internet applications – Internet Serivces
4.3 Newsgroup
A newsgroup just likes a bulletin board. There are tens of thousands of newsgroups entertain global discussions on thousands of topics, including your favourite celebrities or professional teams. Newsgroups are organized by topic. The topic, and sometimes subtopics, is embedded in the newsgroup name. To participate in a newsgroup, user needs newsreader software or similar software that is built into most Internet browser clients. Nowadays, many newsgroups are maintained within the World Wide Web and newsreader software is not required.
Generally, newsgroups are public, anyone can post message and any posted replies to that message as a ______________. It is a series of messages that are replies to each other.
Exercise4.10 Use Outlook Express to connect a news server (news.school.net.hk) and subscribe an
interest group (say test).
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Original Message
Threads
Newsgroup.computer.hardware
Name of newsgroup
Name of Sub-topic
Name of topic
4.4 Online Chat
4.4.44.1.1 Chat RoomsChat RoomsAn online chat is a ____________ typed conversation that takes place on a computer. A chat room is a location on an Internet server that permits users to chat with each other. Anyone in the chat room can participate in the conversation, which usually is specific to a particular topic. Users only need to type a line of text on their computer keyboard, the words they enter display on the computer screens of other people in the same chat room. Some chat rooms support ________ chats and _________ chats, in which people hear or see each other as they chat.
4.4.44.2.2 Instant Messaging (IM)Instant Messaging (IM)Instant messaging is a ___________ Internet communications service that notifies you when one or more people are online and then allows you to exchange messages or files or join a private chat room with them.
ICQICQ (pronounced “I seek you”) is one of the most popular instant messaging software programs available. Users can use ICQ for text chats, to send e-mail message, and to exchange files and URLs with other users. In addition, ICQ lets users chat with groups of people to participate in group meetings or to play games.
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Add people to the messenger list.
Send an instant message
Join a chat room
Internet applications – Internet Serivces
4.5 Webcasting
Many companies use push Technology to webcast, or broadcast news. Web broadcasting is streaming audio or video over the Internet. Live or pre-recorded events can be transmitted to an unlimited worldwide audience. __________________ is a technology that refers to the continuous transmission of data, typically audio or video. You may view a video while downloading.Viewers only need the browser _____________ from Real Player, Windows Media Player or QuickTime player to watch video. They also need a pair of speaker to hear the audio. Plug-inMost Web browsers have the capability of displaying basic multimedia elements on a Web page. Sometimes, a browser might need an additional program, called a plug-in. Plug-in enables Web browsers to display or play a specific files, such as audio or video, that you request. When you install a Web browser, many popular plug-ins are often installed with it. When you encounter a Web page that requires a plug-in you do not have, the Web page might display a message telling you that you are missing a required plug-in, or a dialog box might open and provide a way for you to install the missing plug-in.Common plug-in applicationsType Plug-in Application Description
Document Acrobat ReaderView, navigate and print Portable Document Format (PDF) files.
Multimedia
Flash Player
View dazzling graphics and animation, hear outstanding sound and music, display Web pages across an entire screen.
QuickTimeView animation, music, audio, video, etc… directly in a Web page.
RealOne PlayerListen to live; stream audio and video content for faster viewing; play MP3 files; create music CDs.
Shockwave PlayerExperience dynamic interactive multimedia, 3-D graphics and streaming audio.
Windows Media Player
Listen to live and audio; play or edit WMA and MP3 files; burn CDs; watch DVD movies.
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