Hyperlink
In computing, a hyperlink (or simply link) is a reference to data that the user can directly follow either by clicking or by hovering.
In HTML, hyperlinks are represented by the a (for "anchor") element.
Not to be confused with the link element, which allows authors to link their document to other resources, such as an external style sheet.
Contents
Definition
According to the W3 HTML Recommendation:
A link is a connection from one Web resource to another.A link has two ends -- called anchors -- and a direction. The link starts at the "source" anchor and points to the "destination" anchor, which may be any Web resource (e.g., an image, a video clip, a sound bite, a program, an HTML document, an element within an HTML document, etc.).
Source: 12.1 Introduction to links and anchors @ W3.org
Description
In HTML, a hyperlink points to a whole document or to a specific HTML element within a source code document.
Hypertext is text with hyperlinks.
A software system that is used for viewing and creating hypertext is a hypertext system, and to create a hyperlink is to hyperlink (or simply to link).
The a element
In HTML, the a element represents a hyperlink.
A user following hyperlinks is said to navigate or browse the hypertext.
Source code document
The document containing a hyperlink is known as its source code document.
For example, in an online reference work such as Wikipedia, many words and terms in the text are hyperlinked to definitions of those terms.
Reference mechanisms
Hyperlinks are often used to implement reference mechanisms, such as tables of contents, footnotes, bibliographies, indexes, letters, and glossaries.
Bidirectional hyperlinks
In some hypertext, hyperlinks can be bidirectional: they can be followed in two directions, so both ends act as anchors and as targets. More complex arrangements exist, such as many-to-many links.
Effects of following a hyperlink
The effect of following a hyperlink may vary with the hypertext system and may sometimes depend on the link itself; for instance, on the World Wide Web, most hyperlinks cause the target document to replace the document being displayed, but some are marked to cause the target document to open in a new window.
Transclusion
Another possibility is transclusion, for which the link target is a document fragment that replaces the link anchor within the source document.
Web crawlers
Not only persons browsing the document follow hyperlinks; they may also be followed automatically by programs.
A program that traverses the hypertext, following each hyperlink and gathering all the retrieved documents is known as a Web crawler (or web spider).
See also
External Links
- Hyperlink @ Wikipedia
