I'm working with the fade and slide animations now, and while testing I've hit a couple of points where an element tried to slideIn when it was already ... in, and fadeOut when it was already...out. In both cases the animation starts from the beginning, fully hiding the element and sliding it in or showing the element and fading it out.

I know I can handle it in my code, but the behavior seems a little less intelligent than it could be. If someone calls a fadeout function the end result is display:none - likewise for a slideup. Therefore, if the element style is already display:none the function is technically successful. Can this check be worked into the core logic? It would make the library feel smarter.