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Information about Hyperlink

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A hyperlink, is a reference or navigation element in a document to another section of the same document or to another document that may be on a different website.

Hyperlinks are part of the foundation of the World Wide Web created by Tim Berners-Lee, but are not limited to HTML or the web. Hyperlinks may be used in almost any electronic media.

Hyperlink formats

There are a number of ways to format and present hyperlinks in hypermedia. What distinguishes the various formats of links are the various ways in which links are accessed. Most links are accessed via selecting (pointing and clicking) hypertext or a graphical user interface element (widget) such as a button.

Embedded link

An embedded link is a link embedded in an object such as hyper text or a hot area. The ninth word of this sentence is an example of an embedded hypertext link.

Hot area

A hot area (image map in HTML) is an invisible area of the screen that covers a text label or graphical image. A technical description of a hot area is a list of coordinates relating to a specific area on a screen created in order to hyperlink areas of the image to various destinations, disable linking via negative space around irregular shapes, or enable linking via invisible areas. For example, a map of the world may have each irregular shaped country hyperlinked to further information about that country. A separate invisible hot area interface allows for swapping skins or labels within the linked hot areas without repetitive embedding of links in the various skin elements.

Inline link

An inline link displays remote content without the need for embedding the content. The remote content may be accessed with or without the user selecting the link. Inline links may display specific parts of the content (e.g. thumbnail, low resolution preview, cropped sections, magnified sections, description text, etc.) and access other parts or the full content when needed, as is the case with print publishing software. This allows for smaller file sizes and quicker response to changes when the full linked content is not needed, as is the case when rearranging a page layout.

Random accessed

Random-accessed linking data are links retrieved from a data base or variable containers in a program when the retrieval function is from user interaction (e.g. dynamic menu from an address book) or non-interactive (e.g. random, calculated) process.

Hardware accessed

A hardware-accessed link is a link that activates directly via an input device (e.g. keyboard, microphone, remote control) without the need or use of a graphical user interface.

Hyperlinks in various technologies

Hyperlinks in HTML

Tim Berners-Lee saw the possibility of using hyperlinks to link any unit of information to any other unit of information over the Internet. Hyperlinks were therefore integral to the creation of the World Wide Web.

Links are specified in HTML using the <a> (anchor) elements.

XLink: Hyperlinks in XML

Main article: XLink


The W3C Recommendation called XLink describes hyperlinks which offer a far greater degree of functionality than those offered in HTML. These extended links can be multidirectional, linking from, within, and between XML documents. It also describes simple links which are unidirectional and therefore offer no more functionality than hyperlinks in HTML.

Hyperlinks in other technologies

Hyperlinks are used in e-mails, Text editors, PDF documents, word processing documents, spreadsheets, Apple's HyperCard and many other places.

How hyperlinks work in HTML

A link has two ends, called anchors, and a direction. The link starts at the source anchor and points to the destination anchor. A link from one domain to another is said to be outbound from its source anchor and inbound to its target.

The most common destination anchor is a URL used in the World Wide Web. This can refer to a document, e.g. a webpage, or other resource, or to a position in a webpage. The latter is achieved by means of a HTML element with a "name" or "id" attribute at that position of the HTML document. The URL of the position is the URL of the webpage with "#attribute name" appended — this is a fragment identifier.

When linking to PDF documents from a HTML page the "attribute name" can be replaced with syntax that references a page number or another element of the PDF, for example page=[pageNo] - "#page=386".

Link behavior in web browsers

A web browser usually displays a hyperlink in some distinguishing way, e.g. in a different colour, font or style. The behaviour and style of links can be specified using the Cascading Style Sheets (CSS) language.

In a graphical user interface, the appearance of a mouse cursor may change into a hand motif to indicate a link. In most graphical web browsers, links are displayed in underlined blue text when not cached, but underlined purple text when cached. When the user activates the link (e.g. by clicking on it with the mouse) the browser will display the target of the link. If the target is not a HTML file, depending on the file type and on the browser and its plugins, another program may be activated to open the file.

The HTML code contains some or all of the five main characteristics of a link:
  • link destination ("href" pointing to a URL)
  • link label
  • link title
  • link target
  • link class or link id
It uses the HTML element "a" with the attribute "href" (HREF is an acronym for Hypertext REFerence) and optionally also the attributes "title", "target", and "class" or "id":

<a href="URL" title="link title" target="link target" class="link class">link label</a>


Example: To embed a link into a Page, blogpost, or comment, it may take this form:

Wikipedia


Thus, the complex link string is reduced to, [Wikipedia]. This contributes to a clean, easy to read text or document.

When the cursor hovers over a link, depending on the browser and/or graphical user interface, some informative text about the link can be shown:
  • It pops up, not in a regular window, but in a special hover box, which disappears when the cursor is moved away (sometimes it disappears anyway after a few seconds, and reappears when the cursor is moved away and back). Mozilla Firefox, IE, Opera, and many other web browsers all shows the URL.
  • In addition, the URL is commonly shown in the status bar.
Normally, a link will open in the current frame or window, but sites that use frames and multiple windows for navigation can add a special "target" attribute to specify where the link will be loaded. Windows can be named upon creation, and that identifier can be used to refer to it later in the browsing session. If no current window exists with that name, a new window will be created using the ID.

Creation of new windows is probably the most common use of the "target" attribute. In order to prevent accidental reuse of a window, the special window names "_blank" and "_new" are usually available, and will always cause a new window to be created. It is especially common to see this type of link when one large website links to an external page. The intention in that case is to ensure that the person browsing is aware that there is no endorsement of the site being linked to by the site that was linked from. However, the attribute is sometimes overused and can sometimes cause many windows to be created even while browsing a single site.

Another special page name is "_top", which causes any frames in the current window to be cleared away so that browsing can continue in the full window.

History of the hyperlink

The term "hyperlink" was coined in 1965 (or possibly 1964) by Ted Nelson at the start of Project Xanadu. Nelson had been inspired by "As We May Think," a popular essay by Vannevar Bush. In the essay, Bush described a microfilm-based machine (the Memex) in which one could link any two pages of information into a "trail" of related information, and then scroll back and forth among pages in a trail as if they were on a single microfilm reel. The closest contemporary analogy would be to build a list of bookmarks to topically related Web pages and then allow the user to scroll forward and backward through the list.

In a series of books and articles published from 1964 through 1980, Nelson transposed Bush's concept of automated cross-referencing into the computer context, made it applicable to specific text strings rather than whole pages, generalized it from a local desk-sized machine to a theoretical worldwide computer network, and advocated the creation of such a network. Meanwhile, working independently, a team led by Douglas Engelbart (with Jeff Rulifson as chief programmer) was the first to implement the hyperlink concept for scrolling within a single document (1966), and soon after for connecting between paragraphs within separate documents (1968). See NLS.

Legal issues

See also:


While hyperlinking among pages of Internet content has long been considered an intrinsic feature of the Internet, some websites have claimed that linking to them is not allowed without permission.

In certain jurisdictions it is or has been held that hyperlinks are not merely references or citations, but are devices for copying web pages. In the Netherlands, for example, Karin Spaink was initially convicted of copyright infringement for linking, although this ruling was overturned in 2003. The courts that advocate it see the mere publication of a hyperlink that connects to illegal material to be an illegal act in itself, regardless of whether referencing illegal material is illegal.

In 2000, British Telecom sued Prodigy claiming that Prodigy infringed its patent (U.S. Patent 4,873,662 ) on web hyperlinks. After litigation, a court found for Prodigy, ruling that British Telecom's patent did not cover web hyperlinks. [1]

When linking to illegal or infringing copyrighted content the law of linking liability is currently considered a grey area. There are examples where sites have been proven liable such as Plaintiff Intellectual Reserve vs Utah Lighthouse Ministry, Universal City Studios, Inc. v. Reimerdes, and Comcast vs. Hightech Electronics Inc [2], and there are examples where sites have not been proven liable for linking, for example Perfect 10 v. Google Inc. The cases of websites are proved liable outweigh those where websites were not liable.

Cultural customs/beliefs

In Japan, it is considered rude to link to a personal website, especially that of an artist, without receiving permission beforehand. Some sites use the phrase "Link Free" on their websites to indicate that they will not be upset by unauthorized linking.

See also

References

1. ^ CNET News.com, Hyperlink patent case fails to click. August 23, 2002.
2. ^ WebTVWire.com, Linking to Infringing Video is probably Illegal in the US. December 10, 2006.

External links

reference is a relation between objects in which one object designates, or acts as a means by which to connect to or link to, another object. Such relations may occur in a variety of domains, including linguistics, logic, computer science, art, and scholarship.
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Navigation is the process of planning, recording, and controlling the movement of a craft or vehicle from one place to another.[1] The word navigate is derived from the Latin roots navis meaning "ship" and agere meaning "to move" or "to direct.
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HTML element indicates structure in an HTML document and a way of hierarchically arranging content. More specifically, an HTML element is an SGML element that meets the requirements of one or more of the HTML Document Type Definitions (DTDs).
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document (noun) is a bounded physical representation of body of information designed with the capacity (and usually intent) to communicate. A document may manifest symbolic, diagrammatic or sensory-representational information.
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A website (alternatively, Web site or web site) is a collection of Web pages, images, videos or other digital assets that is hosted on one or several Web server(s), usually accessible via the Internet, cell phone or a LAN.
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World Wide Web (commonly shortened to the Web) is a system of interlinked, hypertext documents accessed via the Internet. With a web browser, a user views web pages that may contain text, images, videos, and other multimedia and navigates between them using hyperlinks.
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Sir Timothy John Berners-Lee, OM, KBE, FRS, FREng, FRSA (born 8 June 1955) is a British developer who with the help of Robert Cailliau invented the World Wide Web. Sir Timothy Berners-Lee is the director of the World Wide Web Consortium (which oversees its continued development),
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HTML (Hypertext Markup Language)

File extension: .html, .htm
MIME type: text/html
Type code: TEXT
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Electronic media are that utilize electronics or electromechanical energy for the end user (audience) to access the content. This is in contrast to static media (mainly print media), which are most often created electronically, but don't require electronics to be accessed by the
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Hypermedia is a term created by Ted Nelson, and used in his 1965 article Complex information processing: a file structure for the complex, the changing and the indeterminate .
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Hypertext most often refers to text on a computer that will lead the user to other, related information on demand. Hypertext represents a relatively recent innovation to user interfaces, which overcomes some of the limitations of written text.
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graphical user interface (GUI) is a type of user interface which allows people to interact with a computer and computer-controlled devices which employ graphical icons, visual indicators or special graphical elements called "widgets", along with text, labels or text
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widget (or control) is an interface element that a computer user interacts with, such as a window or a text box. Widgets are sometimes qualified as virtual to distinguish them from their physical counterparts, e.g.
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button (sometimes known as a command button or push button) is a widget that provides the user a simple way to trigger an event, like searching for a query at a search engine, or to interact with dialog boxes, like confirming his actions.
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In the programming paradigm of object-oriented programming, an object is the individual run-time unit that is used as the basic building block of programs. These objects act on each other, as opposed to a traditional view in which a program may be seen as a collection of functions,
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An example is a representative of a group or a concept. For example, this sentence is one.

You might mean:
  • Exemplum — medieval collections of short stories to be told in sermons

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image map is a list of coordinates relating to a specific image, created in order to hyperlink areas of the image to various destinations (as opposed to a normal image link, in which the entire area of the image links to a single destination).
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IMAGE (from Imager for Magnetopause-to-Aurora Global Exploration), or Explorer 78, was a NASA MIDEX mission that studied the global response of the Earth's magnetosphere to changes in the solar wind.
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electronic page is a term to encompass the grouping of content between basic breaking points in documents that originate or remain as visual electronic documents. This is a software file and recording format term in contrast to electronic paper, a hardware display technology.
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skins may be associated with themes as custom graphical appearances (GUIs) that can be applied to certain software and websites in order to suit the different tastes of different users.
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Inline linking is the placing of a linked object, often an image, from one site into a web page belonging to a second site. The second site is said to have an inline link to the site where the object is located.
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Thumbnails are reduced-size versions of pictures, used to make it easier to scan and recognize them, serving the same role for images as a normal text index does for words.
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Image resolution describes the detail an image holds. The term applies equally to digital images, film images, and other types of images. Higher resolution means more image detail.

Image resolution can be measured in various ways.
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preview may be where output of a particular document, page, film, etc. is displayed before it is produced in its final form. In the case of printed material this is known as a print preview.
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Cropping refers to the removal of the outer parts of an image to improve framing, accentuate subject matter or change aspect ratio. Depending on the application, this may be performed on a physical photograph, artwork or film footage, or achieved digitally using image editing
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For the 2001 album of progressive rock band Yes, see .


Magnification is the process of enlarging something only in appearance, not in physical size. Magnification is also a number describing by which factor an object was magnified.
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Desktop publishing (also known as DTP) combines a personal computer and page layout software to create publication documents on a computer for either large scale publishing or small scale local economical multifunction peripheral output and distribution.
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Page layout is the part of graphic design that deals in the arrangement and style treatment of elements (content) on a page. Beginning from early illuminated pages in hand-copied books of the Middle Ages and proceeding down to intricate modern magazine and catalog layouts, proper
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An input device is a hardware mechanism that transforms information in the external world for consumption by a computer. Often, input devices are under direct control by a human user, who uses them to communicate commands or other information to be processed by the computer, which
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Sir Timothy John Berners-Lee, OM, KBE, FRS, FREng, FRSA (born 8 June 1955) is a British developer who with the help of Robert Cailliau invented the World Wide Web. Sir Timothy Berners-Lee is the director of the World Wide Web Consortium (which oversees its continued development),
..... Click the link for more information.


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