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How can I enable more verbose debug messages for CORS errors in Chrome or Firefox


To enable more verbose debug messages for CORS errors in Chrome or Firefox, you can follow these steps:

Chrome

1. Open the Chrome DevTools by pressing `F12` or `Ctrl+Shift+I`.
2. Go to the "Console" tab.
3. In the Console, type `chrome.webRequest.onErrorOccurred.addListener(function(details) { console.log(details); }, {urls: [""]}, ["blocking"])` and press Enter.

This will log detailed information about any CORS-related errors to the Console, including the specific reason for the CORS violation.

Firefox

1. Open the Firefox Developer Tools by pressing `F12` or `Ctrl+Shift+I`.
2. Go to the "Console" tab.
3. In the Console, type `Services.prefs.setBoolPref("network.console.logCriticalErrors", true)` and press Enter.

This will enable more verbose logging of CORS-related errors in the Firefox Console.

Additionally, you can try the following steps in Firefox to get more detailed CORS error messages:

1. Open `about:config` in the Firefox address bar.
2. Search for the `network.console.logCriticalErrors` preference and set it to `true`.
3. Search for the `dom.serviceWorkers.exemptFromPerDomainMax` preference and set it to `true`.

These settings will provide more detailed information about CORS errors in the Firefox Console.

By using these techniques, you can get more verbose and informative CORS error messages in both Chrome and Firefox, which can greatly assist in debugging CORS-related issues in your web applications.

Citations:
[1] https://stackoverflow.com/questions/20032037/way-to-debug-cors-errors
[2] https://bugzilla.mozilla.org/show_bug.cgi?id=939201
[3] https://www.anycode.ai/tutorial/how-to-debug-javascript-cors-issues-using-the-browser-s-network-panel-to-inspect-http-headers
[4] https://davidtruxall.com/misleading-cors-errors/
[5] https://posthog.com/questions/cors-error-in-firefox-browser