script.aculo.us is a JavaScript library built on the Prototype JavaScript Framework, providing dynamic visual effects and user interface elements via the Document Object Model (DOM).It is most notably included with Ruby on Rails and Seaside, but also provided separately to work with other web application frameworks and scripting languages.script.aculo.us was extracted by Thomas Fuchs from his work on fluxiom, a web based digital asset management tool by the design company wollzelle. It was first released to the public in June 2005.Featuresscript.aculo.us extends the Prototype JavaScript Framework by adding visual effects, user interface controls, and utilities.Visual effectsThere 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 ID of 'id_of_element':<source lang="javascript"> new Effect.Fade('element_id'); </source>