http://
The "http" stands for HyperText Transfer Protocol and
is what enables the browser to
know what protocol it
is going to use to access the information specified in the domain. After the http is
the colon (
: ) and two forward slashes (
// ) that separate the protocol from the remainder of the URL.
Tip: A URL is not explicit to HTTP addresses; HTTPS, FTP, TFTP, Telnet, and other
addresses are also considered URLs and may not follow the same syntax as our
example.
www.
Next, www. stands for World Wide Web and is
used to distinguish the content. This portion of the URL is not required and
many times can be left out. For example, typing "http://computerhope.com" would still
get you to the Computer Hope web page. This portion of the address can also be
substituted for an important sub page known as a subdomain.
For example, http://support.computerhope.com forwards
you to the main help section of Computer Hope.
computerhope.com
Next, computerhope.com is the domain name for the
website. The last portion of the domain is known as the "domain suffix", or TLD, and is used to
identify the type or location of the website. For example, .com is
short for commercial, .org is short for an organization, and .co.uk is the
United Kingdom. There are dozens of other
domain suffixes available. To get a domain, you would register
the name through a domain registrar.
/jargon/u/
Next, the "jargon" and "u" portions of the
above URL are the directories of
where on the server the web page is located. In this example, the web page is
two directories deep, so if you were trying to find the file on the server, it
would be in the /public_html/jargon/u directory. With most
servers, the public_html directory
is the default directory containing the HTML files.
url.htm
Finally, url.htm is the actual web page on the domain you're
viewing. The trailing .htm is the file extension of
the web page that indicates the file is an HTML file. Other
common file extensions on the Internet include .html, .php, .asp, .cgi, .xml, .jpg, and .gif. Each of these file
extensions performs a different function, just like all the different types of
files on your computer.
- See
our index.htm definition
for additional information about this important file.
Tip: As you may have noticed the protocol, domain, directories,
and files are all separated by forward slashes (
/ ).
What characters are not allowed in a URL?
Most people realize that a space is
not allowed in a URL. However, it is also important to realize, as documented
in RFC 1738,
the URL string can only contain alphanumeric characters and the !$-_+*'(),
characters. Any other characters that are needed in the URL must be encoded.
Understanding more complex URLs and parameters
When a URL points to a script that performs additional
functions, such as a search engine pointing to a search results page,
additional information (parameters)
is added to the end of the URL. Below is additional information about a URL
that points to the Computer Hope Search page, with the search query of
"example search".
http://www.computerhope.com/cgi-bin/search.cgi?q=example%20search
In this URL, the script file being pointed to is search.cgi in
the cgi-bin directory. Because this file ends with .cgi, it is assumed to be a Perl script.
After the script file name is a ? (question mark).
The question mark in a URL separates the URL from all the parameters or variables that
are being sent to the script. In the above example, the parameter being sent is q=example%20search.
The "q" is a variable name, and the "example%20search" is
the value being sent to that variable. Because no spaces are allowed in a URL,
the space has been encoded as %20. In
many scripts, a + (plus) is also used to
represent a space.
In our example, because there is a variable the script would use
it as it is executed. Scripts are also not limited to only one variable. If the
script needs multiple variables, each variable can be separated with an & (ampersand)
as shown in the example below.
http://www.computerhope.com/cgi-bin/search.cgi?q=example%20search&example=test
In the above example, there are two different variables. The
"q" variable equals "example search" and the
"example" variable equals "test". If the script was looking
for an example variable, it could be processed and perform an
additional feature.
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