URL

URL

A Uniform Resource Locator (URL), colloquially termed a web address, is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it. URLs are used to retrieve web pages, image files, video files, and other types of digital content.

Overview

URLs occur most commonly to reference web pages, but are also used for file transfer, email, database access, and many other applications. A URL is technically a type of Uniform Resource Identifier (URI), but in many technical documents and verbal discussions, URL is often used as a synonym for URI, and this is not considered a problem.

Syntax

A URL has the following format: scheme:[//[user:password@]host[:port]][/]path[?query][#fragment]

Here the scheme specifies the Internet protocol (such as http or ftp). The host specifies the IP address or domain name where the resource is located. The path specifies the specific resource in the host that the web client wants to access. For example, in the URL http://www.example.com/index.html, 'http' is the scheme, 'www.example.com' is the host, and 'index.html' is the path.

History

The concept of a URL was first defined by Tim Berners-Lee and the World Wide Web Consortium (W3C) in 1994. It was a key innovation that made the World Wide Web possible. Before the introduction of URLs, web resources were accessed by their IP address, which was less user-friendly and less flexible.

See also

• Uniform Resource Identifier
• Domain name
• IP address
• World Wide Web
• Tim Berners-Lee

References

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