A uniform resource locator (URL) is a unique identifier for a web resource through which that resource can be retrieved. The format of most URLs is as follows:
The port number usually is included only if it differs from the default used by the relevant protocol. The URL used to generate the HTTP request shown earlier is as follows:
In addition to this absolute form, URLs may be specified relative to a particular host, or relative to a particular path on that host.
These relative forms are often used in web pages to describe navigation within the website or application itself.