In http1.1(http://www.w3.org/Protocols/rfc2616/rfc2616-sec8.html), it says:
When a client or server wishes to time-out it SHOULD issue a graceful close on the transport connection. Clients and servers SHOULD both constantly watch for the other side of the transport close, and respond to it as appropriate.
MY question is : How to issue a graceful close in both http server and browser side when time out?