100 Continue
Only a part of the request has been received by the server, but as long as it has not been rejected, the client should continue with the request
101 Switching Protocols
The server switches protocol
200 OK
The request is OK
201 Created
The request is complete, and a new resource is created
202 Accepted
The request is accepted for processing, but the processing is not complete
203 Non-authoritative Information  
204 No Content  
205 Reset Content  
206 Partial Content
300 Multiple Choices
A link list. The user can select a link and go to that location.  Maximum five addresses
301 Moved Permanently
The requested page has moved to a new url
302 Found
The requested page has moved temporarily to a new url
303 See Other
The requested page can be found under a different url
304 Not Modified  
305 Use Proxy  
306 Unused
This code was used in a previous version.  It is no longer used, but the code is reserved
307 Temporary Redirect
The requested page has moved temporarily to a new url
400 Bad Request
The server did not understand the request
401 Unauthorized
The requested page needs a username and a password 
402 Payment Required
You can not use this code yet 
403 Forbidden
Access is forbidden to the requested page 
404 Not Found
The server can not find the requested page 
405 Method Not Allowed
The method specified in the request is not allowed
406 Not Acceptable
The server can only generate a response that is not accepted by the client
407 Proxy Authentication Required
You must authenticate with a proxy server before this request can be served
408 Request Timeout
The request took longer than the server was prepared to wait
409 Conflict
The request could not be completed because of a conflict
410 Gone
The requested page is no longer available
411 Length Required
The "Content-Length" is not defined. The server will not accept the request without it
412 Precondition Failed
The precondition given in the request evaluated to false by the server
413 Request Entity Too Large
The server will not accept the request, because the request entity is too large
414 Request-url Too Long
The server will not accept the request, because the url is too long.  Occurs when you convert a "post" request to a "get" request with a long query information
415 Unsupported Media Type
The server will not accept the request, because the media type is not supported
416  
This code still no information
417 Expectation Failed
500 Internal Server Error
The request was not completed. The server met an unexpected condition
501 Not Implemented
The request was not completed. The server did not support the functionality required
502 Bad Gateway
The request was not completed. The server received an invalid response from the upstream server
503 Service Unavailable
The request was not completed. The server is temporarily overloading or down
504 Gateway Timeout
The gateway has timed out 
505 HTTP Version Not Supported
The server does not support the "http protocol" version