如下的javascrip源代码，谁可以看了鼠标特效后帮我具体解释一下每一个函数等的作用。还有就是一个额外的问题，为什么特效里出现的星星是在鼠标旁边出现而不是在别的地方出现呢，它是怎样通过调用源代码实现的？
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