Informational. HTTP 1.0 reserves this class of code for future use. HTTP 1.1 uses codes in this class to indicate the request has been received by the server and that processing is continuing.
Success. The request was successfully received, and the action successfully performed. i.e.
200 OK: The information returned with the response is dependent on the method used in the request.
Redirection. When a response has a redirection code, the client needs to make a further request to actually get the specified resource. The URL of the actual resource is included in the response header field
Location. When the status code is set to 301, the browser automatically makes the request for the URL specified in the
Locationheader field. The use of the
Locationheader field is discussed further in Chapter 5, and used in many examples throughout this tutorial.
301 Moved Permanently: permanent redirection
302 Moved Temporarily: temporary redirection
Client error. The request can't be processed due to bad syntax of the message, the sender is unauthorized or forbidden to access the resource, or the resource can't be found.
400 Bad Request
404 Not Found
Server error. The server failed to fulfill an apparently valid request.
500 Internal Server Error
501 Not Implemented
503 Service Unavailable
550 Permission denied
The actual code used for a particular response is largely determined by the configuration of the web server, and not by a scripting environment that might create a web application. Some scripting environments allow the web developer to explicitly set these codes. For example, a script associated with a URL might simply set the response code to
501 to indicate the requested function hasn't been implemented.