SharedArrayBuffer.prototype.byteLength

The byteLength accessor property represents the length of an SharedArrayBuffer in bytes.

Description

The byteLength property is an accessor property whose set accessor function is undefined, meaning that you can only read this property. The value is established when the shared array is constructed and cannot be changed.

Examples

Using byteLength

var sab = new SharedArrayBuffer(1024);
sab.byteLength; // 1024

Specifications

Specification
ECMAScript (ECMA-262) The definition of 'SharedArrayBuffer.prototype.byteLength' in that specification.

Browser compatibility

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`byteLength`	Chrome Full support 68 Full support 68 No support 60 — 63 Notes Notes Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This was a temporary removal while mitigations were put in place.	Edge Full support 79 Full support 79 No support 16 — 17 Notes Notes Support was removed to mitigate speculative execution side-channel attacks (Windows blog).	Firefox Full support 79 Full support 79 Full support 57 Notes Disabled Notes Support was disabled by default to mitigate speculative execution side-channel attacks (Mozilla Security Blog). Disabled From version 57: this feature is behind the `javascript.options.shared_memory` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support 55 — 57 No support 46 — 55 Disabled Disabled From version 46 until version 55 (exclusive): this feature is behind the `javascript.options.shared_memory` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	IE No support No	Opera No support No	Safari No support 10.1 — 11	WebView Android No support 60 — 63 Notes No support 60 — 63 Notes Notes Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This is intended as a temporary measure until other mitigations are in place.	Chrome Android No support 60 — 63 Notes No support 60 — 63 Notes Notes Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This is intended as a temporary measure until other mitigations are in place.	Firefox Android Full support 57 Notes Disabled Full support 57 Notes Disabled Notes Support was disabled by default to mitigate speculative execution side-channel attacks (Mozilla Security Blog). Disabled From version 57: this feature is behind the `javascript.options.shared_memory` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support 55 — 57 No support 46 — 55 Disabled Disabled From version 46 until version 55 (exclusive): this feature is behind the `javascript.options.shared_memory` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Opera Android No support No	Safari iOS No support 10.3 — 11	Samsung Internet Android No support No Notes No support No Notes Notes Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This is intended as a temporary measure until other mitigations are in place.	nodejs Full support 8.10.0

Legend

Full support: Full support
No support: No support
See implementation notes.: See implementation notes.
User must explicitly enable this feature.: User must explicitly enable this feature.