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URLs- Pointers to the Internet
Now it is time to include links to information available on the
Internet using the World Wide Web's addressing scheme for writing HTML anchor
tags.
Objectives
After this lesson you will be able to:
- Identify the function of Uniform Resource Locators (URLs).
- Recognize the structure of a URL
Lesson
Note: For this lesson, you will not need your HTML text file.
What is a URL?
The Uniform
Resource Locator (URL) is what the WWW uses to find the location
of files and documents from computers on the Internet. On your WWW browser
screen, the URL for this document is displayed in the upper part of
the Web browser window. The URL includes:
- an identifier for the type of Internet server;
- an Internet address; and
- a file path to the particular item of interest.
The URL is what you will need to build a link from the HTML document
you are creating to connect to some other piece of information
available on the Internet. For more information, see
Curling Up To URLs (v0.2)
How are URLs Structured?
The structure of a URL is:
type://in.ter.net.address/ directory/sub-directory/... /filename
The "type"
indicates the type of Internet server being
accessed:
http
- A World Wide Web server that provides World Wide Web documents. "HTTP"
stands for HyperText Transfer Protocol.
gopher
- an Internet Gopher site, menu driven directories of files and
information
ftp
- An anonymous File Transfer Protocol (FTP) site, archives of
files
telnet
- Initiates a Telnet session to log on remotely to another
computer. When selected, your WWW browser will launch a Telnet external program
and connect to the specified site.
WAIS
- Wide Area Indexed Server- a site to search a collection of
subject oriented documents by keywords
file
- A file on your local computer system (hard drive, floppy, local
file server)
The type is always followed by "://" and the Internet adress
of a remote computer. This is in the structure of:
host.domain.domain.domain
For example:
machine.department.college.edu
123.45.6.78
company.com
agency.branch.gov
machine.organization.country
If the URL is to the main level of this host, then the URL is
terminated with a backslash "/". If you are pointing at a
sub-directory or a file, you must also add the exact path to that
item using the backslash character to indicate the file path.
Experimenting With URLs
Note that the URL can point to any site, directory, subdirectory,
text file, image, digital movie, or sound file on any Internet site
that is set up for public access. From the list below, look at the
URL and then see what happens when you select an anchor tag
that uses the URL:
Sample URLs
http
- http://www.mcli.dist.maricopa.edu/
MCLI's WWW server
-
http://www.mcli.dist.maricopa.edu/laby-forum.html
Another WWW document from MCLI
-
http://www.mcli.dist.maricopa.edu/GIFs/read.gif
A graphic image from MCLI
-
http://www.mcli.dist.maricopa.edu/sounds/welcome.au
A sound file from MCLI
gopher
- gopher://marvel.loc.gov/
Library of Congress Gopher.
-
gopher://marvel.loc.gov/11/research/locis
Sub directory of Library of Congress Gopher
-
gopher://marvel.loc.gov/00/locis/hours
File on Library of Congress Gopher
ftp
- ftp://m-media.muohio.edu/
Multimedia Developers FTP site
-
ftp://m-media.muohio.edu/MultiMedia
Sub directory of Multimedia Developers FTP site
-
ftp://m-media.muohio.edu/MultiMedia/0read1st.txt
Text file from Multimedia Developers FTP site
-
ftp://m-media.muohio.edu/MultiMedia/ShowPict.sea.hqx
Download a Macintosh program from Multimedia Developers FTP site
-
ftp://m-media.muohio.edu/MultiMedia/utilities.dir/RunAPW.ZIP
Download a DOS application from Multimedia Developers FTP site
Review Topics
- What purpose do URLs serve for the World Wide Web?
- Where are URLs found on a WWW screen?
- What is the basic structure of an URL?
- What are some different servers that can be accessed using URLs?
Independent Practice
Find some sites on the Internet that intrigue you. For each one,
record its name and its URL displayed near the top of the WWW browser
window. You will use this list later to add anchor links from your
own WWW pages to these sites that you found. Or better yet,
investigate the Bookmarks or Hotlist features of your Web
browser.
Coming Next....
You will use URLs in anchor tags to create links to file
Internet for your Volcanoes! page.
| Lesson Index |
previous lesson " Links to Local Files" |
next lesson "Links to the Internet" |
Writing HTML Lesson 8b: URLs- Pointers to the Internet
©1995
Maricopa Center for Learning & Instruction (MCLI)
Maricopa County Community College District, Arizona
The Internet Connection at MCLI is
Alan Levine--}
Comments to levine@maricopa.edu