jQuery animation for undifined number of <li>'s
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I know this code is super lame but it was working very well 'till now so I kept it. 
But now I have too many < li >'s and I can't add them manually in the js because it's on wordpress and it depends on the category page so the number of < li >'s changes every time. 

My question is; **how can I keep that animation and make it work with an undefined number of < li >'s without having to add them manually? And Is there a way to stop the scroll bar scrolling-away without using the css overflow-y: hidden ?!**

HERE'S THE DEMO:
http://jsfiddle.net/NdRDh/


thank You very much! 
hope You can help me!!

Tom