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Web Design References

Web Design Glossary: H

H

Half-Leading
In CSS half-leading is the leading split in half and applied equally to the top and bottom edges of the element's content-area. The difference between font-size and line-height, is applied equally above and below the content-area for each element.
HCI
HCI stands for "Human Computer Interaction." It is the study of how people relate to electronic tools and interfaces.
Head Pointer
A device attached to the user's head, that allows a user to move the pointer on the screen, (usually moved by the mouse, a pointing device, the arrow keys, or with the movement of their head). It is useful for people who have limited mobility.
Headings
In HTML there are 6 levels of headings, h1 through to h6. To maintain the logical structure of a document, headings should follow a logical progression. Headings of level 3 shouldn't follow directly from headings of level 1, only from headings of level 2. You should always try to maintain a distinction between appearance and logic. Simply because an element is a heading of level 2 does not mean that it will be rendered larger and bolder than regular text in the document. Style sheets allow a web designer to very easily apply any styling to a heading. Keep in mind too, that there are browsers which don't display information in a visual way, relying on text to speech conversion, or Braille conversion. For maximum accessibility, structural elements such as headings should be used correctly, and appropriately. Also consult structure.
Hearing Disability
The condition of a person who experiences partial or total loss of hearing.
Heuristic (Expert) Evaluation
Heuristic evaluation is where a group of usability experts scrutinize a website and evaluate each element of the site against a list of commonly accepted principles or rules of thumb. They apply their training and experience to conduct independent evaluations. Research shows that such evaluations can identify a majority of the usability problems, with the problem-identification percentage increasing as evaluators are added. The major drawback of heuristic evaluation is that evaluators, regardless of their skill and experience, remain surrogate users (expert evaluators who emulate users) and not necessarily typical users of the product. For more information consult Heuristic Evaluation.
Hexadecimal
Hexadecimal numbers are used in HTML and CSS, and other computing applications, to represent colors. The bytes represent the red, green and blue components of the color. One byte represents a number in the range 00 to FF (in hexadecimal notation), or 0 to 255 in decimal notation. Concatenating three bytes in hexadecimal notation forms the hex triplet. The system uses numbers from 0 to 9 and letters from a to f in any combination of six (and starting with an octothorpe) to represent the correlating red, green, and blue colors (#RRGGBB). e.g. #FFFFFF = 255, 255, 255 = white.
Hierarchy
Hierarchy is a top down organizational structure.
Horizontal Scrolling
Horizontal scrolling is scrolling sideways within a web browser's window. When a site has content that is wider than the browser window, users must scroll horizontally to see it. Horizontal scrolling should be avoided if possible. It's awkward to do and users hate it.
Hue
Hue is the name of a distinct color of the spectrum (e.g. red, green, yellow, orange, blue). It is the particular wavelength frequency.
HyperText Markup Language (HTML)
The markup language that is used on most of the World Wide Web to create web pages. The standards for HTML are controlled by the W3C.