What is MooTools ?
It is sometimes called My Object-Oriented Tools .
The MooTools can also be integrated in Visual Studio .
More Details on the MooTools is available here.
The MooTools 1.3 beta 1 was launched on 27th April with lots of improvements .
This is what the MooTools Site states on the MooTools 1.3
Visit MooTools Official site for more details to download the version.