A specially formatted sequence of
characters representing a location on the Internet. The
URL contains three parts:
the network protocol, the host name or address, and the file location.
The network protocol determines the underlying Internet
protocol to be used to reach the location; it consists of a standardized name
of a protocol followed by a colon and two forward slashes (://). Common
protocols in URLs include ftp://, http://,
and mailto://.
The host immediately comes after the protocol definition,
represented by its fully qualified hostname, as found in the DNS or by its IP address. For example, a URL of http://www.askme.com
contains both the protocol and the host data required to access this Website.
The file part of a URL defines the location of a resource on
the server. Resources are files that can be documents, graphics, or plain-text
files.
A URL such as http://www.askme.com has an implicit file
location that most Web servers (for example, Apache) interpret to refer to a
specific filename such as “index.htm.” All other files exist in a hierarchical
directory structure under the root, such as /library/glossary/abglossary
.htm. A full URL would look like this:
http://www.askme.com/library/glossary/abglossary.htm.
When creating HTML
pages, developers can choose to use relative file locations—such as
“../pics/image.gif,” which locates the file “image.gif” in a subdirectory
“pics’ of the directory containing the current file—or complete URLs, but most
on the Internet use complete
URLs.
See Also:
Browser; Domain Name System (DNS); HTML or HyperText Markup Language; HTTP
(HyperText Transfer Protocol); Internet; IP Address.
Further Reading.
About, Inc. URL. [Online, 2004.] About, Inc. Website. http://
compnetworking.about.com/library/glossary/bldef-url.htm.
