A Uniform Resource Locator (URL) is a string of characters used to identify a network resource. URLs are commonly used to identify web pages, but can also point to other resources, such as images and documents.
A URL is composed of several components. The scheme is the first part of the URL and indicates the protocol used to access the resource. For example, a URL beginning with http://
indicates that the Hypertext Transfer Protocol (HTTP) should be used to access the resource. The domain name is the second part of the URL and identifies the server hosting the resource. The path is the third part of the URL and indicates the location of the resource within the server.
The query string is an optional part of the URL and is used to provide additional information to the server. It follows the path and is separated from it by a question mark (?
). The query string contains a sequence of key-value pairs, with each pair separated by an ampersand (&
).
The first URL was proposed as part of the Hypertext Transfer Protocol (HTTP) in 1989. It was designed to provide a simple way to identify web resources. Since then, the URL has become the de facto standard for identifying network resources.
URLs are designed to be human-readable and easy to remember. They are also designed to be machine-readable, which allows them to be used by computers to locate resources. URLs are also extensible, which means they can be used to identify a variety of different types of resources.
The following is an example of a URL:
http://example.com/path/to/resource?key1=value1&key2=value2
This URL indicates that the Hypertext Transfer Protocol (HTTP) should be used to access the resource located at /path/to/resource
on the server example.com
. The query string contains two key-value pairs, key1=value1
and key2=value2
.
The main advantage of URLs is that they are human-readable and easy to remember. They also provide a way to access resources without having to know the exact location of the resource. However, URLs can be difficult to type in correctly, and they can become very long and complex when used to identify complex resources.
URLs are closely related to the Hypertext Transfer Protocol (HTTP), which is used to access resources identified by URLs. URLs are also related to Uniform Resource Identifiers (URIs), which are used to identify resources in a more general way.
URLs are often used to identify web pages, but they can also be used to identify other types of resources, such as images, documents, and even other computers on a network.
URLs are an important part of the modern web. They provide a way to identify and access resources on the web in a human-readable and machine-readable way.