mootools

From the guys that brought us moo.fx comes the next big thing mootools – an ultra compact javascript framework. Awesome stuff!

mootools is a very compact, modular, Object-Oriented javascript framework. Its unique design makes it extremely crossbrowser, easy to use, and a snap to extend with your own code. It comes with a choice of more than fifteen scripts, plugins and addons, including Effects (moo.fx) Ajax (moo.ajax), Dom Navigator (moo.dom), Drag and Drop, Sortable lists, cookies Manager and many more.