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The AbstractWorker.onerror property of the AbstractWorker interface represents an EventHandler, that is a function to be called when the error event occurs and bubbles through the Worker.


myWorker.onerror = function() { ... };


The following code snippet shows creation of a Worker object using the Worker() constructor and setting up of an onerror handler on the resulting object:

var myWorker = new Worker('worker.js');

myWorker.onerror = function() {
  console.log('There is an error with your worker!');


Specification Status Comment
HTML Living Standard
The definition of 'AbstractWorker.onerror' in that specification.
Living Standard  

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support4 Yes3.51010.64
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support4.44.4 Yes411.55.1 ?

Cross-origin worker error behaviour

In earlier browser versions, trying to load a cross-origin worker script threw a SecurityError; in newer browsers an error event is thrown instead due to a spec change. Find out more information on how to deal with this in Loading cross-origin worker now fires error event instead of throwing; worker in sandboxed iframe no longer allowed.

See also

Document Tags and Contributors

 Contributors to this page: fscholz, chrisdavidmills, nmve, erikadoyle, teoli, tregagnon
 Last updated by: fscholz,