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What is a Hyperlink and Hypertext?

Last Edit: 17/08/17

Hypertext is a term that was coined by Ted Nelson in 1965, and was outlined in his book "Literary Machines" which referred to it as "non-sequential text fragments that are linked together with hotspots called hypertext links." Hypertext has been defined as all the following: non-sequential writing; formatted text; user interface; text with hyperlinks; text that links to information; fields of information that are linked together; and software that can drive hardware. As originally stated by Ted Nelson, hypertext documents are connected together through the use of hyperlinks, which are embedded in the text of the hypertext document; the syntax/language of hypertext and hyperlinks differs for the various hypertext systems that have been designed. Hypertext is displayed on an electronic display, and hyperlinks are clicked/hover upon using a pointing device that controls a graphical user interface. Hyperlinks are often referred to as a "link".

The Mother of All Demos

Douglas Engelbart displaying hypertext at "The Mother of All Demos"

The first working example of hypertext was displayed at "The Mother of All Demos", which was a 90-minute presentation given by Douglas Engelbart in 1968 at the Fall Joint Computer Conference in San Francisco. During the presentation Engelbart used a mouse to browse pages of information, and click on underlined text that would load another page of text. Engelbart's system is generally referred to as a "first generation" hypertext system; another first generation hypertext system was ZOG, developed at Carnegie Mellon University during the 1970s, and IBM's Generalized Markup Language (GML), which was designed by Edward Mosher, Charles Goldfarb, and Raymond Lorie in the early 1970s.

The "second generation" of hypertext systems included: Tim Berners-Lee's ENQUIRE system; Don McCracken and Rob Akscyn's Knowledge Management System (KMS); and Ben Shneiderman's HyperTies system - which were all developed in the early 1980s. Most of these early hypertext systems were developed for academic/research environments, such as CERN, and rarely made their way into commercial retail software. The first information system that incorporated hypertext, and was used by all segments of society, was the World Wide Web: Tim Berners-Lee, its inventor, explained why he used hypertext for the web: "HyperText is a way to link and access information of various kinds as a web of nodes in which the user can browse at will."

The original language, invented by Tim Berners-Lee, to create hypertext documents for the World Wide Web was the: Hypertext Markup Language (HTML). Berners-Lee has stated that HTML is based upon the Standard Generalized Markup Language (SGML), which is turn was based upon IBM's Generalized Markup Language (GML). Hyperlinks within HTML have a simple design: by standard, underlined blue text, that give no indication of where they will lead the user. Sophisticated hyperlinks tend to give the user more information concerning the hyperlink: providing information about the document the link is pointing too and the reason for the link.

Hyperlinks in HTML: usually include text or an image, which are hovered over with a pointing device (mouse, touchpad) and are clicked upon. The syntax for a HTML hyperlink is as follows, and has remained the same since Tim Berners-Lee designed HTML.

Hyperlink featuring text: <a href="">Homepage</a>
Hyperlink featuring an image: <a href=""><img src="mother-of-all-demos.jpg"></a>

The HTML code for a hyperlink features three components:

1) <a></a> tag
2) href (hypertext reference) that can be a URL, id within a page, email address, JavaScript etc
3) text, image etc, that identify what is being linked too