Percent-encoding, also known as URL encoding, is a mechanism for encoding
information in a Uniform Resource Identifier (URI) under certain
circumstances. Although it is known as URL encoding it is, in fact, used
more generally within the main Uniform Resource Identifier (URI) set, which
includes both Uniform Resource Locator (URL) and Uniform Resource Name
(URN). As such it is also used in the preparation of data of the
"application/x-www-form-urlencoded" media type, as is often used in the
submission of HTML form data in HTTP requests.