The unhandledrejection event is fired when a JavaScript Promise is rejected but there is no rejection handler to deal with the rejection.

Bubbles No
Cancelable No
Target objects defaultView
Interface PromiseRejectionEvent


The unhandledrejection event implements the PromiseRejectionEvent interface, which inherits from Event. You can use the properties and methods defined on these interfaces.


window.addEventListener("unhandledrejection", function (event) {
  console.warn("WARNING: Unhandled promise rejection. Shame on you! Reason: "
               + event.reason);


Specification Status Comment
WHATWG HTML Living Standard Living Standard Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 49 No support[1] No support No support No support
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support[1] No support No support No support

[1] In Firefox, this is implemented but disabled by default. To turn it on, go to about:config and set the dom.promise_rejection_events.enabled pref to true.

See also

Document Tags and Contributors

 Contributors to this page: chrisdavidmills, gkalpak, fscholz, Sheppy
 Last updated by: chrisdavidmills,