You may want to respond with a 205 after a user submits a form. A 205 would tell the client code that the data has been processed and the form should be reset.
The 205 (Reset Content) status code indicates that the server has fulfilled the request and desires that the user agent reset the "document view", which caused the request to be sent, to its original state as received from the origin server.
This response is intended to support a common data entry use case where the user receives content that supports data entry (a form, notepad, canvas, etc.), enters or manipulates data in that space, causes the entered data to be submitted in a request, and then the data entry mechanism is reset for the next entry so that the user can easily initiate another input action.
Since the 205 status code implies that no additional content will be provided, a server MUST NOT generate a payload in a 205 response. In other words, a server MUST do one of the following for a 205 response: a) indicate a zero-length body for the response by including a Content-Length header field with a value of 0; b) indicate a zero-length payload for the response by including a Transfer-Encoding header field with a value of chunked and a message body consisting of a single chunk of zero-length; or, c) close the connection immediately after sending the blank line terminating the header section.
Source: RFC 7231 Section 6.3.6