Help implementing callback function or clearing form values

[V]

I'm having trouble implementing a callback function into a new Jquery comment system I'm working on.

 

This is the main comments page that displays all the comments.

 

http://www.phpriot.com/2973

 

And this http://www.phpriot.com/2972 inserts a new comment into the DB and displays it without refreshing the page. Problem is, the form values aren't cleared up after submitting. I was advised to use a callback function as an alternative to refreshing the page but I'm not sure how to.. Or instead of a callback isn't there a simple code that will clear all form inputs upon clicking submit?