Hypertext

Hypertext, in computer science, a collection of documents that contain cross-references called hyperlinks, which allow the user to jump easily from one document to another. Hypertext is used extensively on computer networks and the Internet, as well as in many multimedia applications.

Hypertext documents may exist as stored program files on the user’s hard drive, on external memory storage devices, or on the server computers that make up the Internet and smaller, more localized networks. Computers need a program called a browser to view hypertext. Browsers usually highlight hyperlinks within the plain text, showing them in bold or in a different color. To access a document through a hyperlink, the user points at the hyperlink with a device called a mouse and clicks a button. The browser then downloads and displays the document targeted by the hyperlink. Moving between hypertext documents is called navigating. On the Internet, every hypertext document has a unique address, called a Uniform Resource Locator (URL), that permits other hypertext documents to locate it.

Hypertext documents are based on and created in a markup language—a programming language specially designed to give structure to documents on networks. The most general markup language is Standard Generalized Markup Language (SGML). Hypertext documents on the Internet are created in a more specialized type of markup language called Hypertext Markup Language (HTML). In HTML, tags are embedded in text to determine how the user views the document in the browser. The tags integrate the hyperlinks into hypertext and enable links to other documents, e-mail to other Internet users, graphics, audio, and video.

Multimedia is the integration of graphics, sound, video, and text, and it is often incorporated within hypertext to create hypermedia. Hypermedia, like multimedia, is usually graphics intensive, mixing photographs, pictures, icons, animations, sound, and video. In comparison to the earlier text-only Internet, this enriched multimedia environment is considered to be the reason why the World Wide Web and the Internet have become so popular.

Hypertext allows users to interact with other users and experience completely different sets of information, links, and media—all from the same starting point. One application of hypertext is hyperfiction. In hyperfiction a user who is reading a fictional work on a computer can direct the path and outcome of the action, often in multimedia, by making certain selections. Whether textual or not, many computer applications, especially in entertainment and reference, operate on similar principles of users specifying choices from a vast number of possibilities.

The term hypertext was coined by American computer scientist Ted Nelson in 1965 to describe textual information that could be accessed in a nonlinear way. He used the prefix hyper to describe the speed and facility with which users could jump to and from related areas of text.