This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The crossOriginIsolated read-only property of the WindowOrWorkerGlobalScope interface returns a boolean value that indicates whether a SharedArrayBuffer can be sent via a Window.postMessage() call.

This value is dependant on any Cross-Origin-Opener-Policy and Cross-Origin-Embedder-Policy headers present in the response.


var myCrossOriginIsolated = self.crossOriginIsolated; // or just crossOriginIsolated


A boolean value


if(crossOriginIsolated) {
  // Post SharedArrayBuffer
} else {
  // Do something else


Specification Status Comment
HTML Living Standard
The definition of 'crossOriginIsolated' in that specification.
Living Standard Initial definition.

Browser compatibility

ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Chrome No support NoEdge No support NoFirefox Full support 72IE No support NoOpera No support NoSafari No support NoWebView Android No support NoChrome Android No support NoFirefox Android No support NoOpera Android No support NoSafari iOS No support NoSamsung Internet Android No support No


Full support
Full support
No support
No support
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.

See also