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Hypertext is text that contains hyperlinks. A hyperlink is an automated cross-reference to another location on the same document or to another document which, when selected by a user, causes the computer to display the linked location or document within a very short period of time. Hypertext is a type of database that is well suited for handling large chunks of text. A database is a set of data that has a regular structure and that is organized in such a way that a computer can easily find the desired information. Hypertext documents can be static or they can be dynamically generated. A static document is one that is prepared in advance and appears in the web browser as is. A dynamically generated document is one that does not exist in a final form but, rather, is produced according to user input, such as according to information that a user enters on a form. Hypertext can add greatly to the efficiency of the organization and utilization of information. This is because it can allow one copy of a document to exist at a single location that can serve as a reference from a large number of other documents, rather than requiring each of the documents to maintain a separate copy of that document. It is also because it can eliminate the need for users to take the extra steps of looking for related information in indexes and glossaries and because it can often replace the use of search mechanisms. Hypertext is a type of hypermedia, which can include not only text but also images (both still and moving) and sound. That is, hyperlinks embedded in text can cause the display not only of other text but also of images (both still and moving) and replaying of sound, and hyperlinks embedded in images can cause the display of text or other images or the replay of sound. For complete symmetry, some efficient means might also be found for embedding hyperlinks in sound. The concept of hypertext existed long before the technology became available to make it practical. A major milestone was the 1945 article As We May Think by Vannevar Bush in The Atlantic Monthly. Bush described a futuristic device he called a Memex, which was a mechanical desk linked to an extensive library of microfilms and able to display books, texts or any document from that library. The Memex was also able to automatically follow references from any given page to the specific page referenced. The terms hypertext and hypermedia were coined in the 1960s by Theodor Holmes Nelson, the founder of Project Xanadu (the goal of which was to develop a computer network with a simple user interface). A number of experimental hypertext and hypermedia programs were developed in the early 1980s, some of whose features and terminology were eventually incorporated into the web. The concept of hypertext was further popularized by the introduction of HyperCard by Apple Computer in 1987, although most people still failed to see its true significance. The most familiar example of hypertext today is, of course, the web. However, standalone documents can also consist of hypertext or hypermedia. An example is PDF (portable document format) documents that contain hyperlinks to other pages in the same document. Created August 25, 2006. |