303 error

An HTTP response with this status code will additionally provide a  URL  in the  Location   header field. The  User Agent  (e.g. a web browser) is invited by a response with this code to make a second, otherwise identical, request, to the new URL specified in the Location field. The HTTP/1.0 specification ( RFC 1945 ) defines this code, and gives it the description phrase "Moved Temporarily".

Many web browsers implemented this code in a manner that violated this standard, changing the request type of the new request to GET, regardless of the type employed in the original request (e.g. POST).[1]  For this reason, HTTP/1.1 (RFC 2616) added the new status codes 303 and 307 to disambiguate between the two behaviours, with 303 mandating the change of request type to GET, and 307 preserving the request type as originally sent. Despite the greater clarity provided by this disambiguation, the 302 code is still employed in web frameworks to preserve compatibility with browsers that do not implement the HTTP/1.1 specification.[2]



