There are five core effects script.aculo.us offers: Opacity, Scale, MoveBy, Highlight, and Parallel. Through these effects there are over 16 additional effects using combinations of the core effects out of the box. Programmers can also extend existing and create new effects.
Enabling an effect is a matter of assigning an element with an ID name and one line of code for the effect. Below is an example for the Effect.Fade effect applied to a DOM element with an ID of 'message-box':
This will cause the target ID to fade in opacity and end by setting the CSS "display" property to "none".
Various other settings within the effect can be modified, such as the duration of the effect and the range of the effect:
This would fade the element, but stop when the effect is 80% complete (with an opacity of 20%).