W3cubDocs

/HTTP

Connection

The Connection general header controls whether or not the network connection stays open after the current transaction finishes. If the value sent is keep-alive, the connection is persistent and not closed, allowing for subsequent requests to the same server to be done.

Except for the standard hop-by-hop headers (Keep-Alive, Transfer-Encoding, TE, Connection, Trailer, Upgrade, Proxy-Authorization and Proxy-Authenticate), any hop-by-hop headers used by the message must be listed in the Connection header, so that the first proxy knows it has to consume them and not forward them further. Standard hop-by-hop headers can be listed too (it is often the case of Keep-Alive, but this is not mandatory).

Syntax

Connection: keep-alive
Connection: close

Directives

close
Indicates that either the client or the server would like to close the connection. This is the default on HTTP/1.0 requests.
any comma-separated list of HTTP headers [Usually keep-alive only]
Indicates that the client would like to keep the connection open. Having a persistent connection is the default on HTTP/1.1 requests. The list of headers are the name of the header to be removed by the first non-transparent proxy or cache in-between: these headers define the connection between the emitter and the first entity, not the destination node.

Browser compatibility

Feature Chrome Firefox Edge Internet Explorer Opera Safari
Basic Support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Edge mobile Firefox for Android IE mobile Opera Android iOS Safari
Basic Support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Connection