Actually I was thinking that maybe the request.onsuccess and request.onerror functions are unnecessary because we don't have to care about the sent is success or not, or I should say we don't have to do anything on success and error. And do you think IAC needs the callback functions for onsuccess and onerror? probably I can add them first to the second and third parameters, and if the IAC need them, you can just pass the callbacks to the second and third parameters.