Join the Mozilla’s Test Days event from 9–15 Jan to test the new Firefox address bar on Firefox Beta 135 and get a chance to win Mozilla swag vouchers! 🎁

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Natao arisiva ity resaka mitohy ity. Mametraha fanontaniana azafady raha mila fanampiana.

When I click on Firefox I get a pop-up that says: Java Script Application TypeError:Components.Classics[cid] is undefined. IS THIS DANGEROUS?

  • 1 valiny
  • 1 manana an'ity olana ity
  • 5 views
  • Valiny farany nomen'i cor-el

more options

Java Script Application X

! Type Error:Components.classics[cid] is undefined

                                     OK
Java Script Application X ! Type Error:Components.classics[cid] is undefined OK

All Replies (1)

more options

This issue can be caused by an extension that isn't working properly.


Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).