Show Javascript error count in Firefox without opening console

Question

Now that Firebug has been subsumed into Firefox, how can I configure the browser to bring Javascript errors to my attention without having the console open all the time, as Firebug used to do by showing an error count on its toolbar icon?

Answer 1

The Firefox DevTools provide a so-called "Developer Toolbar" aka GCLI (openable via Firefox menu > Developer > Developer Toolbar or Shift + F2), which displays the number of errors on the page (besides providing many useful commands):

Update:

The DevTools team obviously plans to remove the Developer Toolbar, because of low usage and because it's unmaintained and for most of it's features are available somewhere else.

There is no replacement yet for the error count, though, but a comment on the related bug report indicates that it will be added back.

Answer 2

Another options is to use Chrome extension JavaScript Errors Notifier. To install it in Firefox, you'll first have to install another extension Chrome Store Foxified, which enables you to install any Chrome extension from Chrome Web Store to Firefox. You can follow the instructions of Chrome Store Foxified to install the extensions you like. (Note that not all Chrome extensions will work in Firefox.)

If you want to install the Chrome extension permanently, you'll have to sign up with Mozilla to get the extension signed.

If the JavaScript Errors Notifier extension is successfully installed in Firefox, you'll see an icon appearing at the right end of the address bar.

And when there's any JavaScript error in the page, the icon will turn red. To see the details of the errors, you can click on the icon. And the extension have quite some options to tune the errors that you want to get alerted.