200 OK request was processed successfully
301 Moved permanently document has been moved
304 Not modified if cached version is up-to-date
400 Bad request syntax error in client’s request
403 Forbidden client is not allowed access (e.g., protected)
404 Not found file could not be found
500 Internal server error server failed
503 Service unavailable server is overloaded
In addition to the status code, the server’s response may include
Date response time (in GMT)
Server identification info on the server
Last-modified time document was last changed (in GMT)
Content-length size of document, in bytes
Content-type file format (e.g., html, gif, pdf)
Expires prevents browser from caching beyond date
