Dynamic HTML, or DHTML, refers to the ability to change style or positioning properties with a scripting language. Timelines use dynamic HTML to change the properties of layers and images in a series of frames over time. Use timelines to create animations that do not require any ActiveX controls, plugins, or Java applets.
Timelines create animation by changing the position, size, visibility, and stacking order of a layer over time. Timelines are also useful for other actions that you want to occur after a page loads. For example, timelines can change the source file of an image, and they can execute behaviors at a particular time. The layer functions of timelines work only in 4.0 or later browsers.
To see the JavaScript code generated by a timeline, open the HTML inspector. The timeline code is in the MM_initTimelines function, inside a SCRIPT tag in the HEAD of the document.
When editing the HTML of a document containing timelines, be careful not to move, rename, or delete anything that a timeline refers to.