Web/API/WindowEventHandlers/onunhandledrejection

The onunhandledrejection property of the WindowEventHandlers mixin is the EventHandler for processing unhandledrejection events. These events are raised for unhandled Promise rejections.

Syntax

window.onunhandledrejection = function;

Value

function is an EventHandler or function to call when unhandledrejection events are received by the window. The event handler receives as an input parameter as a PromiseRejectionEvent.

Examples

This example simply logs unhandled rejections' reason values to the console.

window.onunhandledrejection = function(e) {
  console.log(e.reason);
}

Specifications

Specification	Status	Comment
HTML Living StandardThe definition of 'onunhandledrejection' in that specification.	Living Standard	Initial definition.

Browser compatibility

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
`onunhandledrejection`	Chrome Full support 49	Edge Full support ≤79	Firefox Full support 69 Full support 69 Full support 68 Disabled' Disabled' From version 68: this feature is behind the `dom.promise_rejection_events.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. Partial support 55 Notes' Disabled' Notes' This event handler was added in Firefox 55 but was disabled since it wasn't fully implemented. It was fully implemented in Firefox 68 and enabled by default in Firefox 69. Disabled' From version 55: this feature is behind the `dom.promise_rejection_events.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	IE No support No	Opera Full support 36	Safari Full support 11	WebView Android Full support 49	Chrome Android Full support 49	Firefox Android Full support 68 Disabled' Full support 68 Disabled' Disabled' From version 68: this feature is behind the `dom.promise_rejection_events.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. Partial support 55 Notes' Disabled' Notes' This event handler was added in Firefox 55 but was disabled since it wasn't fully implemented. It was fully implemented in Firefox 68 but not enabled by default. Disabled' From version 55: this feature is behind the `dom.promise_rejection_events.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Opera Android No support No	Safari iOS Full support 11.3	Samsung Internet Android Full support 5.0

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.

WindowEventHandlers.onunhandledrejection by Mozilla Contributors is licensed under CC-BY-SA 2.5.