CloseEvent

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.

Constructor

CloseEvent()

Creates a new CloseEvent.

Properties

This interface also inherits properties from its parent, Event.

CloseEvent.code Read only

Returns an unsigned short containing the close code send by the server. The following values are permitted status codes. The following definitions are sourced from the IANA website [Ref].

Status code	Name	Description
0–999		Reserved and not used.
1000	Normal Closure	Normal closure; the connection successfully completed whatever purpose for which it was created.
1001	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	Protocol Error	The endpoint is terminating the connection due to a protocol error.
1003	Unsupported Data	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	No Status Recvd	Reserved. Indicates that no status code was provided even though one was expected.
1006	Abnormal Closure	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	Invalid frame payload data	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	Policy Violation	The endpoint is terminating the connection because it received a message that violates its policy. This is a generic status code, used when codes 1003 and 1009 are not suitable.
1009	Message too big	The endpoint is terminating the connection because a data frame was received that is too large.
1010	Missing Extension	The client is terminating the connection because it expected the server to negotiate one or more extension, but the server didn't.
1011	Internal Error	The server is terminating the connection because it encountered an unexpected condition that prevented it from fulfilling the request.
1012	Service Restart	The server is terminating the connection because it is restarting. [Ref]
1013	Try Again Later	The server is terminating the connection due to a temporary condition, e.g. it is overloaded and is casting off some of its clients. [Ref]
1014	Bad Gateway	The server was acting as a gateway or proxy and received an invalid response from the upstream server. This is similar to 502 HTTP Status Code.
1015	TLS Handshake	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. Available for registration at the IANA via first-come, first-serve.
4000–4999		Available for use by applications.

CloseEvent.reason Read only

Returns a DOMString indicating the reason the server closed the connection. This is specific to the particular server and sub-protocol.

CloseEvent.wasClean Read only

Returns a Boolean that Indicates whether or not the connection was cleanly closed.

Methods

This interface also inherits methods from its parent, Event.

CloseEvent.initCloseEvent()

Initializes the value of a CloseEvent created. If the event has already being dispatched, this method does nothing. Do not use this method anymore, use the CloseEvent() constructor instead.

Browser compatibility

[1] 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.

[2] 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.

See also

• WebSocket