Presentations of information can respond dynamically to human interaction. To work in these terms requires:

• visual design and programming
• conceptualization of the initial information, and how it will change.
• sense of what gesture will trigger dynamic change
• understanding of who the human is, and what s/he is doing

JavaScript

This apparently innocuous scripting language exists in industrial strength implmentations. These days, compatability is suprisingly good across platforms and browsers. (This is for JavaScript, not CSS!) It is standardized as ECMAScript, by the European Computer Manufacturers Association.

Document Object Model

Each HTML document is structured as a tree of elements. As such, it is amenable to algorithms such as depth-first search. Each element has attrbitutes. The structure of the tree, and the values of the attributes can be manipulated dynamically, using JavaScript.

Event Handling

While basic JavaScript event handling is not part of any W3C standard, it is a defacto standard that works across browsers. For more advanced interaction, the CSS2 event handling standard is implemented in Mozilla. IE 5 & 6 have their own incompatible event model. This results in some platform specific complexities.