呵呵，我尝试着用英语回答一下， 不要拍砖啊。。。

actually it is the jquery itself which is being used in the codeschool online courses.
just in case that you would like to delve into the details on how the animation works in JavaScript(or in jQuery), please refer to the following web pages
http://javascript.info/tutorial/animation
http://easings.net/
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