If the service associated with the processing of a form has side effects (for example, modification of a database or subscription to a service), the method should be `POST'.
To process a form whose action URL is an HTTP URL and whose method is `POST', the user agent conducts an HTTP POST transaction using the action URI, and a message body of type `application/x-www-form- urlencoded' format as above. The user agent should display the response from the HTTP POST interaction just as it would display the response from an HTTP GET above.