CloseEvent is sent to clients using WebSockets when the connection is closed. This is delivered to the listener indicated by the
- Creates a new
This interface also inherits properties from its parent,
- Returns an
unsigned shortcontaining the close code send by the server. The following values are permitted status codes. The following definitions are sourced from the IANA website [Ref]. Note that the 1xxx codes are only WebSocket-internal and not for the same meaning by the transported data (like when the application-layer protocol is invalid). The only permitted codes to be specified in Firefox are 1000 and 3000 to 4999 [Source, Bug].
Status code Name Description
Reserved and not used.
Normal Closure Normal closure; the connection successfully completed whatever purpose for which it was created.
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.
Protocol Error The endpoint is terminating the connection due to a protocol error.
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).
Reserved. A meaning might be defined in the future.
No Status Recvd Reserved. Indicates that no status code was provided even though one was expected.
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.
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).
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.
Message too big The endpoint is terminating the connection because a data frame was received that is too large.
Missing Extension The client is terminating the connection because it expected the server to negotiate one or more extension, but the server didn't.
Internal Error The server is terminating the connection because it encountered an unexpected condition that prevented it from fulfilling the request.
Service Restart The server is terminating the connection because it is restarting. [Ref]
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]
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.
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).
Reserved for future use by the WebSocket standard.
Reserved for use by WebSocket extensions.
Available for use by libraries and frameworks. May not be used by applications. Available for registration at the IANA via first-come, first-serve.
Available for use by applications.
- Returns a
DOMStringindicating the reason the server closed the connection. This is specific to the particular server and sub-protocol.
- Returns a
Booleanthat Indicates whether or not the connection was cleanly closed.
This interface also inherits methods from its parent,
- Initializes the value of a
CloseEventcreated. If the event has already being dispatched, this method does nothing. Do not use this method anymore, use the
|Basic support||Yes||Yes||81 2||10||Yes||?|
|No||Yes||8 — 41||No||No||No|
|Feature||Android webview||Chrome for Android||Edge mobile||Firefox for Android||Opera Android||iOS Safari||Samsung Internet|
|No||No||Yes||8 — 41||No||No||?|
1. Prior to Firefox 12, the close code
CLOSE_NORMAL was used when the channel was closed due to an unexpected error or unspecified error condition.
2. Prior to Firefox 8, the
WebSocket close event was sent to the listener as a simple event.