Help understanding jQuery button enable/disable code

Question

I grabbed this code form JCarousel and just trying to understand these lines below. I\'m new to jQuery and not that great at JavaScript so I am not sure what is jQuery and

Answer 1

These two lines check if there are any "next" or "prev" items to display and enables/disables the buttons accordingly by adding disabled jcarousel-next-disabled(enabled) and setting the disabled attr to true/false.