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Web Design References

Web Design Glossary: D

D

A "description link" that takes the form of a capital "D" and is located near an image. It is linked to a separate page containing a description of the image.
Data Table
A table that is used to present data in a tabular or spreadsheet format. This contrasts with a layout table that uses the same construct for a different purpose. In a data table contents of a cells are related to cell contents in adjacent cells.
Deafness
A condition of a person who cannot hear at all.
Declaration
In CSS, a declaration is part of a statement or rule. It is the portion of the statement, which suggests to a browser how selected elements should be rendered. A declaration contains one or more properties the individual pieces of style to be applied to the selected element. It consists of pair of property and value parameters.
Deep Linking
Deep links are links that go directly to an inner page of a website rather than the homepage. It enables direct linking to highly appropriate and specific content.
Degrade Gracefully
An element on a web page is said to 'degrade gracefully' if ignoring it does not prevent content on the page from being obtainable and functional.
Deliverable
In project management, deliverables are the output of what you are doing. It refers to the defined end products, results, or services of a project.
Deprecated
In HTML 4 a deprecated element or attribute was one that has been outdated by newer constructs. The term does not exist in HTML5.
Descendant Selectors
At times, authors may want selectors in CSS to match an element that is the descendant of another element in the document tree (e.g., "Match those EM elements that are contained by an H1 element"). Descendant selectors express such a relationship in a pattern. A descendant selector is made up of two or more selectors separated by white space. A descendant selector of the form "A B" matches when an element B is an arbitrary descendant of some ancestor element A.
Device Independence
For Web content to be device independent, it should be possible for a user to obtain a functional presentation associated with its Web page identifier via any access mechanism.
Digital Divide
The gap that exists between those who have access to electronic and information technology, and those who do not.
Disability
According to the Americans with Disabilities Act, "The term means, with respect to an individual (A) a physical or mental impairment that substantially limits one or more of the major life activities of such individual; (B) a record of such an impairment; or (C) being regarded as having such an impairment."
Disability Discrimination Act (DDA)
A name shared by two laws passed in Australia (1992) and the United Kingdom (1995). They both prohibit discrimination against people with disabilities. The goal is that a functional presentation should be possible via any access mechanism. The method of presentation may vary according to the different access mechanisms, but the possibility of a functional presentation should always exist.
Dithering
In computer graphics, dithering is a method of creating additional colors and shades from an existing palette by interspersing pixels of different color in computer graphics to create additional colors and shades from an existing palette by interspersing pixels of different colors.
Doctype
Doctype, Document Type Definition (DTD) is a file that defines how applications interpret a document. For more information consult Doctype.
Doctype Switching
A mechanism that was used prior to HTML5 by which browsers examine the DOCTYPE (or lack thereof) contained in a document, and picked a rendering mode to match it.
The tree of elements encoded in the source document. Each element in this tree has exactly one parent, with the exception of the root element, which has none.
Dots Per Inch (DPI)
Dots Per Inch is a term that also refers to printing and the amount of ink that actually is placed upon the print medium. Dots Per Inch is a property of a print graphic and determines how it prints - its size and quality. Color printing isn't done in continuous color. It is done with individual dots of Cyan, Magenta, Yellow and Black (CMYK), lots of them, giving an impression of continuity. These are the dots in DPI. A dot per inch (number of pixels) also measures resolution on output devices such as monitors and printers. Dividing the resolution of the device by the physical dimensions of its imaging region arrives at the horizontal and/or vertical density of the output device.
Dyslexia
A language based learning disability that is often characterized by difficulties with understanding written language, and being more attuned to a graphical or object based learning style.