php+jquery

php+jquery

i can see how jquery can do some sexy things, but i cant get my head around one thing:

how do i do php and javascript at the same time? that is, i can have a delete button under a comment. when i press it, the javascript/jquery has a nice fade out effect for it. but obviously, its not wiped from the database. how would i do that? (not that specifically, but just in general)