◆Error Codes Wiki

Chrome DevTools Errors — Common Console Errors and Debugging Tips

Informationalchrome

Overview

Understand common Chrome DevTools console errors including CORS, CSP, mixed content, and JavaScript errors with practical debugging techniques.

Key Details

  • DevTools Console shows errors, warnings, and log messages from the page and browser
  • Errors are color-coded: red (errors), yellow (warnings), blue (info), gray (verbose/debug)
  • Network tab shows failed requests, CORS errors, and slow resources
  • Source tab allows breakpoint debugging of JavaScript
  • Application tab shows service workers, storage, cache, and manifest data

Common Causes

  • JavaScript runtime errors (TypeError, ReferenceError, SyntaxError) from page scripts
  • CORS errors when fetching cross-origin resources without proper headers
  • CSP violations when loading resources not allowed by the Content Security Policy
  • Mixed content warnings when HTTPS pages load HTTP resources
  • Failed network requests due to server errors, DNS failures, or blocked requests

Steps

  1. 1Open DevTools: F12 or Ctrl+Shift+I (Cmd+Option+I on Mac)
  2. 2Filter console messages: click the filter dropdown to show only Errors, Warnings, or specific levels
  3. 3Click the filename:line link next to any error to jump to the exact source code location
  4. 4Use the Network tab to see failed requests: filter by status (4xx, 5xx) to find errors
  5. 5Right-click a network request > Copy as cURL to reproduce the request in Terminal
  6. 6Use Sources tab breakpoints: click line numbers to set breakpoints, then reproduce the error

Tags

devtoolsconsoledebuggingchromejavascript

Related Items

browser-javascript-errorbrowser-cors-errorbrowser-csp-violations

More in Chrome

chrome-err-connection-refusedChrome ERR_CONNECTION_REFUSED
Warning
chrome-err-connection-timed-outChrome ERR_CONNECTION_TIMED_OUT
Warning
chrome-err-internet-disconnectedChrome ERR_INTERNET_DISCONNECTED
Warning
chrome-err-name-not-resolvedChrome ERR_NAME_NOT_RESOLVED
Warning
chrome-err-ssl-protocol-errorChrome ERR_SSL_PROTOCOL_ERROR
Warning
chrome-err-cert-authority-invalidChrome ERR_CERT_AUTHORITY_INVALID
Error

Frequently Asked Questions

Click the error source link to jump to the code. Set a breakpoint on the line before the error. Reproduce the issue — execution pauses at the breakpoint. Inspect variables in the Scope panel.