Uniform Resource Identifiers (URI) can be one of two things, a Uniform Resource Locator (URL) or a Uniform Resource Name (URN). You likely deal with URLs most of the time. See RFC 3986 for a proper definition of the terms URI, URL and URN
URLs are used to address the individual resources of your website.
URNs are usually used for hooking into other applications, as mailto:, magnet: or spotify: suggest.
While RFC 3986 defines the structure of an URL in depth, URNs are not. The structure (and meaning) of URNs are up to their distinct specifications.
RFC 3986 Section 3 visualizes the structure of URIs as follows:
URL: foo://example.com:8042/over/there?name=ferret#nose \_/ \______________/\_________/ \_________/ \__/ | | | | | scheme authority path query fragment | _____________________|__ / \ / \ URN: urn:example:animal:ferret:nose
authority
__________|_________
/ \
userinfo host
__|___ ___|___
/ \ / \
username password hostname port path & segment query fragment
__|___ __|__ ______|______ | __________|_________ ____|____ |
/ \ / \ / \ / \ / \ / \ / \
foo://username:[email protected]:123/hello/world/there.html?name=ferret#foo
\_/ \ / \ \ / \__________/ \ \__/
| | \ | | \ |
scheme subdomain \ tld directory \ suffix
\____/ \___/
| |
domain filename
In Javascript the query is often referred to as the search.
URI.js provides both accessors with the subtle difference of .search() beginning with the ?-character
and .query() not.
In Javascript the fragment is often referred to as the hash.
URI.js provides both accessors with the subtle difference of .hash() beginning with the #-character
and .fragment() not.
urn:example:animal:ferret:nose?name=ferret#foo
\ / \________________________/ \_________/ \ /
| | | |
scheme path & segment query fragment
While RFC 3986 does not define URNs having a query or fragment component, URI.js enables these accessors for convenience.