Simple question but I cannot find any online documentation for the jquery success event in ajax.
What qualifies as a successfull ajax request?
Does the ajax have to send a value back to the javascript?
And if the above answer is no, how does JQuery know it was a success?
See source here: https://github.com/jquery/jquery/blob/master/src/ajax.js#L520
If the status code is 2xx or 304 (Not modified) then it is considered successful. The server doesn't have to respond with any content beyond the appropriate headers.
Success means the request is successful, eg the server does not return an error code status (400 - 500 range).