Did you try asking google?
http://api.jquery.com/jQuery.ajax/
url:
A string containing the URL to which the request is sent.
data:
Data to be sent to the server. It is converted to a query string, if
not already a string.success(data, textStatus, jqXHR):
A function to be called if the request succeeds.
solved Explain some javascript/jquery code [closed]