Tim Berners-Lee, research article

, 1989

The World Wide Web (WWW) is an information space where documents and other web resources are identified by Uniform Resource Locators (URLs), interlinked by hypertext links, and can be accessed via the Internet. English scientist Tim Berners-Lee invented the World Wide Web in 1989. He wrote the first web browser computer program in 1990 while employed at CERN in Switzerland. The Web browser was released outside CERN in 1991, first to other research institutions starting in January 1991 and to the general public on the Internet in August 1991.

The World Wide Web has been central to the development of the Information Age and is the primary tool billions of people use to interact on the Internet.

Web pages are documents, typically HTML documents, that are almost always accessible via HTTP, the Hypertext Transfer Protocol. This allows users to retrieve web pages from a web server and to view them on a client device, typically a web browser. All publicly accessible websites that have been registered with a domain name server are assigned a unique IP address. A website can be hosted on a single server or, more commonly, distributed across multiple servers.

A web server processes incoming network requests over HTTP and provides resources from its file system. A web client, such as a web browser, initiates a request to a web server for a resource using HTTP. The server, which provides resources such as HTML documents and other web resources, responds with the requested resource. The communication between client and server is typically done using the Hypertext Transfer Protocol (HTTP).

The most common file format for web pages is Hypertext Markup Language (HTML). HTML is a markup language that web browsers use to interpret and compose text, images, and other material into visual or audible web pages. Default file extensions for HTML files are .htm or .html.

Web pages can contain links to other resources, such as images, video, and other files. A web browser can also be used to download these resources from a web server for local display or storage.

The Hypertext Transfer Protocol (HTTP) is a communication protocol for retrieving resources from a server. A client, such as a web browser, establishes a connection to a server and sends a request for a resource, such as an HTML document. The server responds with the requested resource or an error message if the resource could not be found.

HTTP is a stateless protocol, which means that each request from a client is independent of any other request. This allows for scalability, as a server does not need to maintain a connection with a client for each request.

The first version of HTTP, HTTP/0.9, was developed by Tim Berners-Lee in 1991. It was a simple protocol for retrieving resources from a server.

HTTP/1.0, the first official version of HTTP, was released in 1996. It added support for headers, which allows for more information to be exchanged between the client and server.

HTTP/1.1, the current version of HTTP, was released in 1999. It adds support for persistent connections, virtual hosting, and other features.