Web/API/WebSocket/send

The WebSocket.send() method enqueues the specified data to be transmitted to the server over the WebSocket connection, increasing the value of bufferedAmount by the number of bytes needed to contain the data. If the data can't be sent (for example, because it needs to be buffered but the buffer is full), the socket is closed automatically.

Syntax

WebSocket.send("Hello server!");

Parameters

data

The data to send to the server. It may be one of the following types:

USVString

A text string. The string is added to the buffer in UTF-8 format, and the value of bufferedAmount is increased by the number of bytes required to represent the UTF-8 string.

ArrayBuffer

You can send the underlying binary data used by a typed array object; its binary data contents are queued in the buffer, increasing the value of bufferedAmount by the requisite number of bytes.

Blob

Specifying a Blob enqueues the blob's raw data to be transmitted in a binary frame. The value of bufferedAmount is increased by the byte size of that raw data.

ArrayBufferView

You can send any JavaScript typed array object as a binary frame; its binary data contents are queued in the buffer, increasing the value of bufferedAmount by the requisite number of bytes.

Exceptions thrown

INVALID_STATE_ERR

The connection is not currently OPEN.

SYNTAX_ERR

The data is a string that has unpaired surrogates.

Note: Gecko's implementation of the send() method differs somewhat from the specification in Gecko 6.0; Gecko returns a boolean indicating whether or not the connection is still open (and, by extension, that the data was successfully queued or transmitted); this is corrected in Gecko 8.0.

As of Gecko 11.0, support for ArrayBuffer is implemented but not Blob data types.

Specifications

Specification	Status	Comment
HTML Living StandardThe definition of 'WebSocket: send' in that specification.	Living Standard	Initial definition

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
send	Chrome Full support 4	Edge Full support 12	Firefox Full support 18 Notes' Full support 18 Notes' Notes' See bug 775368. No support 11 — 18 Notes' Notes' Only parameter of type ArrayBuffer and String supported. No support 8 — 11 Notes' Notes' Only parameter of type String supported. No support 4 — 8 Notes' Notes' Only parameter of type String supported. Returns boolean.	IE Full support 10	Opera Full support 12.1	Safari Full support 5	WebView Android Full support ≤37	Chrome Android Full support 18	Firefox Android Full support 18 Notes' Full support 18 Notes' Notes' See bug 775368. No support 14 — 18 Notes' Notes' Only parameter of type ArrayBuffer and String supported. No support 8 — 14 Notes' Notes' Only parameter of type String supported. No support 4 — 8 Notes' Notes' Only parameter of type String supported. Returns boolean.	Opera Android Full support 12.1	Safari iOS Full support 4.2	Samsung Internet Android Full support 1.0

Legend

Full support  

Full support

See implementation notes.'

See implementation notes.

WebSocket.send() by Mozilla Contributors is licensed under CC-BY-SA 2.5.