Animating layers

Dynamic HTML, or DHTML, refers to the combination of HTML with a scripting language that allows you to change the style or positioning properties of HTML elements. Timelines in Dreamweaver use dynamic HTML to change the properties of layers and images over time. Use timelines to create animations that do not require any ActiveX controls, plug-ins, or Java applets (but do require JavaScript).

NOTE

The word dynamic can mean different things in different web-related contexts. Don’t confuse Dynamic HTML with the idea of a dynamic web page, which means a web page generated dynamically by server-side code before being served to a visitor.

Timelines allow you to change the position, size, visibility, and stacking order of a layer. (The layer functions of timelines work only in 4.0 or later browsers.) 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 tag so different images appear in the page over time.

To see the JavaScript code generated by a timeline, open the Document window’s Code view. The timeline code is in the MM_initTimelines function, inside a script tag in the head section of the document.

When editing the HTML of a document containing timelines, make sure you do not move, rename, or delete anything that a timeline refers to.