Dynamic HTML is a term that collectively describes the DOM (Document Object Model) and the script activated mechanisms for changing the content of a web page either interactively or not. The content of the page can be animated or modified as a result of the user moving the mouse or clicking on items in the page. The event model is also a contributing factor as is Style sheet support for abstraction of content and appearance by means of CSS (Cascading Style Sheets) and the absolute positioning of HTML elements.

Really the term Dynamic HTML should be deprecated in favor of "DOM scripting" and "CSS scripting".