HTTP Response Codes

2** Success

200 OK
201 Created: Following a POST command, this indicates success, but the text of the response line indicates the URL of the new document.
202 Accepted: Request accepted for asynchronous processing.
203 Partial Information: Returned information may be cached or private.
204 No Response: Used for scripts that don't return a visible result.

301 Moved: Browsers with link editing capabilities should automatically link to the new reference.
The response contains one or more header lines of the form
URI: <url> string CrLf which specify alternative addresses for the object in question. The string is an optional comment field.
302 Found: Same as move, except that linking to the found address doesn't make much sense, since the document URL is expected to change.
This is the code that the httpd returns for a cgi script whose output contained a Location: header.
303 Method: Same as found, but a different method may be used to access the document; details about the method are sent in the message body.
304 Not modified: Use the local copy if you cached it.

400 Bad Request: Impossible request or syntax error
401 Unauthorized: Request should be retried with proper authorization header.
402 Payment Required: Request should be retried with proper charge-to header.
403 Forbidden: Authorization will not help
404 Not found: A document with that URL doesn't exist.
411 No such group: (NCSA httpd) the newsgroup in news:newsgroup doesn't exist.