Be it AJAX, drag and drop, auto-completion, advanced visual effects, or many other features, all you need is write one or two lines of script that look so good they could almost pass for Ruby code! Prototype and script.aculo.us libraries are treasure troves, smoothing over all the usual core differences between browsers, and make the most common features easy to implement. Dive into Prototype, the library that makes JavaScript so much more powerful, and it looks a lot like Ruby code. When it comes to advanced UI features, script.aculo.us is every web developer's dream come true: whether you need to create auto-completed text inputs, implement an editor in place, providing customized behavioral drag-and-drop, capture your users attention with visual effects or simply build DOM fragments more efficiently, it's all there, and lightweight too. This book guides you through all the details of this feature, lets you use many technologies on the server side, such as PHP, vanilla Ruby, and Ruby On Rails, in many examples that illustrate each aspect.