Lecture 2a: The
World Wide Web
What You Will Learn Today
- Describe the process of creating a dial-up connection to the Internet.
- Define basic web terms such as WWW, link, HTML, page, site, browser, server
and URL.
- Describe the organisation of files and directories on the Internet and
their access through URLs.
- Explain the transfer of information between web
browsers and servers that
occurs during browsing.
- List and compare features of browsers and associated software.
- Obtain a computer with a modem, an RJ-11 phone cable and a
telephone land line.
- Obtain an Internet connection from a provider such as
Uganda Telecom or
Africa Online.
- Choose a provider and service based on the speed and hours per month you
need and the cost you can afford.
- Use the RJ-11 cable to connect the modem to the telephone. Connect
the telephone to the telephone line.
- If you have an external modem, you must also connect the modem to
the the computer's serial port.
- Configure the dial-in software to dial the telephone
number and enter the username and password the provider gave
you.
- An icon for the connection is normally created on the desktop.
- Click the connection icon, then click Dial.
- After a minute or two you will normally be connected and can start using
the Internet and e-mail.
- When finished, click Disconnect to hang up.
- The World Wide Web is an international hypertext system that links
together millions of documents.
- A hypertext link is a word or picture which requests a different
file from the Internet when you click on it.
- Hypertext meta language (HTML) is a set of codes which is used to
create formatted hypertext documents.
- A web page is a document created using hypertext.
- A web site
is a collection of related pages.
- Web pages and sites can be stored on the hard drive of a local computer or a web
server on the Internet.
- A web browser is a program that displays web pages it retrieves.
- Popular browsers include Microsoft Internet Explorer, Netscape
Navigator, Mozilla, and Konqueror.
- A Uniform Resource Locator (URL) is the address (location) of a
file (resource) on the web.
- The Address box of the browser shows the URL of the currently
displayed document.
- You can type a URL into the Address box to go directly to a site or
document.
- A URL has at least a protocol and server. It may also have a port, path,
filename and anchor.
- A protocol indicates the type of resource and necessary
communication procedures for getting it
- e.g. http = hypertext documents, ftp = file transfer,
mailto = e-mail addresses, news = newsgroups
- A server is denoted by the domain name or IP number.
- A port number indicates the program on the server to handle the
request; it can usually be omitted
- e.g. by default http=80, ftp=21, telnet=23, mail=25
- A filename is the name of the file on the server; it may include a
path of folders
- An anchor is a place in a hypertext file where the browser jumps,
instead of starting at the top. It starts with a #.
- The user uses a web browser and clicks on a document link.
- The browser reads the URL of the link and recognizes the different parts
of the URL.
- The client (the user's computer) contacts the web server (through the appropriate
port number)
and requests the file.
- The server retrieves the file from its storage device (e.g. a hard disk).
- If no filename is specified, the default page (usually the home page) is
retrieved.
- If the file is a program, the program is run on the server.
- If the file contains images, those are also retrieved, one by one.
- The server sends the results of the request to the web browser, usually in
the form of a HTML document.
- The web browser reads the HTML codes, formats the document and images, and
displays the results for the user to see.
- Sketch a diagram to show the flow of information.
- The back button returns you to the page you last visited.
- The forward button reverses the action of the back button.
- The home button takes you back to a page your browser has chosen as
the home page.
- Your browser's home page opens when you open the browser.
- You can change the home page by opening the Preferences or
Internet Options dialog box listed in the browser menus.
- "Use Current" makes the current page the default. "Use Blank" opens a
browser window more quickly.
- The reload or refresh button redisplays a page that has been
changed or did not display properly.
- The stop button stops loading or downloading a page or file that is
taking too long.
Revisiting Pages
- The history button lists all the pages you have recently visited,
and makes it easy to return
- Bookmarks or favorites store addresses so you can easily
return to them later. You can organize them into folders.
Other Browser Features
- Print the current page or selection and change the page setup.
- Save the current page as multiple files, a single archive file,
HTML only (no pictures), or plain text (no formatting).
- Copy text and pictures (after selecting by dragging with the mouse) and paste them into a word processor or
graphics editor.
- Search the current page for a string of text.
- Using view options, change the displayed text size, view or hide
toolbars, and view the HTML source codes.
- Run other applications, e.g. read mail, read news, edit
web pages, use FTP, make Internet calls, use a calendar, use a
contact list.
- Install and use plug-ins to view certain types of multimedia files
like Shockwave, QuickTime or RealAudio.
To Do After Class
- Read Hofstetter ch. 4, Surfing the Net.
- Read
Computers
in Your Future module 8a:
exploring
the web, first half.
- Look at the
Internet Links page
provided by the UMU Library.
- View the lists of web navigation software for
Windows and
Linux.
- Become familiar with the Konqueror and Mozilla
web browsers.
- Find out how you use the features listed above.
- Browse some of the sites in the books listed above.