158 Glossary Glossary Accessibility The degree to which a website can be understood by as many people as possible, including those with disabilities Achromatic In colour schemes, the absence of hue and saturation ­ just black, white and the greys in between Achromatic greys Made from mixing just black and white together with no other colour ActionScript Flash's object-oriented programming language Additive colour Colour created by superimposing ASP (Active Server Pages) A scripting language that allows web pages to be compiled `on the fly' from a constantly updated database Behaviour In Dreamweaver, this is a JavaScript combination of an event and the action triggered by that event Blog (weblog) An online journal with most recent entries first, which can be customized <br /> A line-break tag: as it has no end tag, we add a space and slash inside the tag Breadcrumbs A navigation aid usually appearing Colour blindness Deuteranomaly is the most common colour deficiency, resulting in a reduction in sensitivity to the green area of the spectrum Colour tetrad Four colours, equally spaced on the colour wheel, containing a primary, its complement and a complementary pair of inter- mediates. Also any organization of colour on the wheel forming a rectangle that could include a double split-complement Colour triad Three colours spaced an equal distance apart on the colour wheel forming an equilateral triangle. Itten's 12-step colour wheel is made up of Deprecation A term applied to methods and tags that have been superseded and should be avoided as the feature will be removed in the future. This gives programmers time to bring their code into compliance with the new standard Dingbat A symbol or ornament such as or + treated as characters in a font <div> HTML tag that creates containers in which to place layout elements DOCTYPE A declaration at the start of every web page that tells the browser what version of the markup