Uniform Resource Locator Explained

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Uniform Resource Locator (URL), still known as Universal Resource Locator, is a technical, Web-related term used in two distinct meanings:

• In popular usage and many technical documents, it is a synonym for Uniform Resource Identifier (URI);
• Strictly, the idea of a uniform syntax for global identifiers of network-retrievable documents was the core idea of the World Wide Web. In the early times, these identifiers were variously called "document names", "Web addresses" and "Uniform Resource Locators". These names were misleading, however, because not all identifiers were locators, and even for those that were, this was not their defining characteristic. Nevertheless, by the time the RFC 1630 formally defined the term "URI" as a generic term best suited to the concept, the term "URL" had gained widespread popularity, which has continued to this day.

URI/URL syntax in brief

Every URI (and therefore, every URL) begins with the scheme name that defines its namespace, purpose, and the syntax of the remaining part of the URI. Most Web-enabled programs will try to dereference a URI according to the semantics of its scheme and a context-vbn. For example, a Web browser will usually dereference a <nowiki>http://example.org/</nowiki> by performing an HTTP request to the host example.org, at the default HTTP port (see Port 80). Dereferencing the URI <nowiki>mailto:bob@example.com</nowiki> will usually start an e-mail composer with the address bob@example.com in the "To" field.

"example.com" is a domain name; an IP address or other network address might be used instead.In addition, https://example2.com denotes a secure (usually) web site.

URLs as locators

In its current strict technical meaning, a URL is a URI that, “in addition to identifying a resource, [provides] a means of locating the resource by describing its primary access mechanism (e.g., its network ‘location’).”^[1]

Address bar

See main article: URL bar.

URLs are typically entered into the address or location bar of a web browser. To the right is a standard Mozilla Firefox address entry. Address bars vary in appearance depending on the web browser displayed in.

See also

• CURIE (Compact URI)
• Extensible Resource Identifier (XRI)
• Internationalized Resource Identifier (IRI)
• Percent-encoding
• Query string
• Rewrite engine
• Uniform Resource Identifier (URI)
• URL normalization
• Website
• URL redirection

External links

• Cool URIs don't change
• RFC-3986 Uniform Resource Identifier (URI): Generic Syntax
• RFC 1738
• RFC-3986 (html)

Notes and References

1. Tim Berners-Lee, Roy T. Fielding, Larry Masinter. (January 2005). “Uniform Resource Identifier (URI): Generic Syntax”. Internet Society. RFC 3986; STD 66.