Expand: date=March 2008

In computing, a Uniform Resource Locator (URL) is a type of Uniform Resource Identifier (URI) that specifies where an identified resource is available and the mechanism for retrieving it. In some cases URL has also stood (for comedy effect) for Ultimate Resource Locator. In popular usage and in many technical documents and verbal discussions it is often, imprecisely and confusingly, used as a synonym for URI. The confusion in usage stems from historically different interpretations of the semantics of the terms involved. In popular language, a URL is also referred to as a Web address.

History

The URL (Universal Resource Locator) was created in 1990 by Tim Berners-Lee as part of the URI.URL Specification, It was later renamed to "Uniform Resource Locator". He regrets the format of the URL. Instead of being divided into the route to the server, separated by dots, and the file path, separated by slashes; he would have liked it to be one coherent hierarchical path.World Wide Web History For example, http://www.serverroute.com/path/to/file.html would look like http://com/serverroute/www/path/to/file.html.

Syntax

main: URI scheme#Generic syntax

Every URL is made up of some combination of the following: the scheme name (commonly called protocol), followed by a colon, then, depending on scheme, a hostname (alternatively, IP address), a port number, the pathname of the file to be fetched or the program to be run, then (for programs such as CGI scripts) a query string , and with HTML files, an anchor (optional) for where the page should start to be displayed.URL Syntax

The combined syntax will look similar to this: resource_type://domain:port/filepathname?query_string#anchor

• The scheme name, or resource type, defines its namespace, purpose, and the syntax of the remaining part of the URL. Most Web-enabled programs will try to dereference a URL according to the semantics of its scheme and a context-vbn. For example, a Web browser will usually dereference the URL http://example.org:80 by performing an HTTP request to the host example.org, at the port number 80. Dereferencing the URN mailto:bob@example.com will usually start an e-mail composer with the address bob@example.com in the To field.
• Other examples of scheme names include https: gopher:, wais:, ftp:. URLs that specify https as a scheme (such as https://example.com/) normally denote a secure website.