WorkerGlobalScope: error event

Baseline Widely available

This feature is well established and works across many devices and browser versions. Its been available across browsers since July 2015.

Learn more
See full compatibility

Note: This feature is only available in Web Workers.

The error event of the WorkerGlobalScope interface fires when an error occurs in the worker.

Syntax

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("error", (event) => { })

onerror = (message, filename, lineno, colno, error) => { }

Note: For historical reasons, onerror on Window and WorkerGlobalScope objects is the only event handler property that receives more than one argument.

For more details about this, see the page for the error event on Window objects.

Event type

A generic Event.

Example

The following code snippet shows an onerror handler set inside a worker:

self.onerror = () => {
  console.log("There is an error inside your worker!");
};

The same snippet, but using addEventListener():

self.addEventListener("error", () => {
  console.log("There is an error inside your worker!");
});

Specifications

Specification
HTML # handler-workerglobalscope-onerror

Browser compatibility

Help improve MDN

Was this page helpful to you?

Yes No

Learn how to contribute

This page was last modified on May 2, 2025 by MDN contributors.

View this page on GitHub Report a problem with this content