All JavaScript Errors

The average number of errors per page view across our dataset.
This is a general estimate of the frequency and prevalence of errors across the web.

errors per 100 page views

Most Common Errors

These errors impact a large percentage of our customers.

Script Error

Script Error is caused by an error in a script loaded from a different domain. The browser's Same Origin Policy obfuscates the real context of the error.

Failed to fetch

A fetch network request is being blocked by the browser. This could be an ad blocker, a CORS error, or because the request is being aborted. This error could be prevented by attaching a catch handler to fetch.

Unexpected token '<'

A network response is being parsed as JSON but contains HTML markup. This often happens because the API has returned an error page rather than the expected payload.

Cannot read properties of undefined (reading 'length')

An attempt to read the length of a String, Array, or similar object, but the object was not defined.

The operation is insecure

This can be caused a few ways, but most commonly caused by a failed attempt to access localStorage while in Safari private mode. It can also be caused by setting browser history outside of the current origin or making an improper network request.

Cannot read properties of undefined (reading 'id')

An attempt to read the id of an Object, but the object was not defined.

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Top Errors

Global JavaScript Error Statistics

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