CloseEvent

This article is in need of a technical review.

A CloseEvent is sent to clients using WebSockets when the connection is closed. This is delivered to the listener indicated by the WebSocket object's onclose attribute.

Attributes

Attribute Type Description
code unsigned long The WebSocket connection close code provided by the server. See Close codes for possible values.
reason DOMString A string indicating the reason the server closed the connection. This is specific to the particular server and sub-protocol.
wasClean boolean Indicates whether or not the connection was cleanly closed.

Close codes

The following values are permitted status codes.

Status code Name Description
0-999   Reserved and not used.
1000 CLOSE_NORMAL Normal closure; the connection successfully completed whatever purpose for which it was created.
1001 CLOSE_GOING_AWAY The endpoint is going away, either because of a server failure or because the browser is navigating away from the page that opened the connection.
1002 CLOSE_PROTOCOL_ERROR The endpoint is terminating the connection due to a protocol error.
1003 CLOSE_UNSUPPORTED The connection is being terminated because the endpoint received data of a type it cannot accept (for example, a text-only endpoint received binary data).
1004   Reserved. A meaning might be defined in the future.
1005 CLOSE_NO_STATUS Reserved.  Indicates that no status code was provided even though one was expected.
1006 CLOSE_ABNORMAL Reserved. Used to indicate that a connection was closed abnormally (that is, with no close frame being sent) when a status code is expected.
1007   The endpoint is terminating the connection because a message was received that contained inconsistent data (e.g., non-UTF-8 data within a text message).
1008   The endpoint is terminating the connection because it received a message that violates it's policy. This is a generic status code, used when codes 1003 and 1009 are not suitable.
1009 CLOSE_TOO_LARGE The endpoint is terminating the connection because a data frame was received that is too large.
1010   The client is terminating the connection because it expected the server to negotiate one or more extension, but the server didn't.
1011   The server is terminating the connection because it encountered an unexpected condition that prevented it from fulfilling the request.
1012-1014   Reserved for future use by the WebSocket standard.
1015   Reserved. Indicates that the connection was closed due to a failure to perform a TLS handshake (e.g., the server certificate can't be verified).
1016-1999   Reserved for future use by the WebSocket standard.
2000-2999   Reserved for use by WebSocket extensions.
3000-3999   Available for use by libraries and frameworks. May not be used by applications.
4000-4999   Available for use by applications.

See also

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support ? 8.0 (8.0) ? ? ?
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? 8.0 (8.0) ? ? ?

Gecko notes

Prior to Gecko 8.0 (Firefox 8.0 / Thunderbird 8.0 / SeaMonkey 2.5), Gecko sent the WebSocket "close" event to the listener as a simple event. Support for CloseEvent was implemented in Gecko 8.0.

Prior to Gecko 12.0 (Firefox 12.0 / Thunderbird 12.0 / SeaMonkey 2.9), Gecko reported the close code CLOSE_NORMAL when the channel was closed due to an unexpected error, or if it was closed due to an error condition that the specification doesn't cover. Now CLOSE_GOING_AWAY is reported instead.

Document Tags and Contributors

Contributors to this page: evilpie, Sheppy, tregagnon, camerondm9, Kennyluck, teoli
Last updated by: camerondm9,