When the client submit something to the server, server confirms but cannot return the result immediately, and serve a page like
<html>
<head>
<meta http-equiv='refresh' content='5; url=/somewhere/else' />
</head>
<body>
Your message is accepted, and the page will back to the home after 5 seconds.
But the browser will put that temporary page in the history. My question is what HTTP status code may I use in this situation to tell the browser not record the URL?
Status code should be 200. If you do not want browser to cache, you should set Cache related meta fields.