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I've just updated firefox to a Firefox 51.0.1 (32-bit), and after the update console.log stopped working.

When I am tring to test some JavaScript variables using console.log(), it doesn't output anything.

Sebastian Zartner
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user3351236
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2 Answers2

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As I mentioned in another answer, this happens because the Firefox internal APIs, which Firebug uses to output the data, have changed. When you open the Browser Console, you'll see the following error:

TypeError: ConsoleAPIListener is not a constructor console.js:149:38

Note that, as stated in a thread in the Firebug discussion group and on the Firebug homepage, Firebug is discontinued and unmaintained. I.e. it breaks more and more with every new version of Firefox and will quit working completely once multi-process Firefox is enabled. There is a blog post explaining the reasons.

The team behind Firebug advises to use the Firefox DevTools instead and there is a migration guide available.

Community
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Sebastian Zartner
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    For the ones who like Firebug display more than DevTools' default, please note that a "Firebug" theme is available in DevTools' options, to keep a flavor of it ! – Bob Apr 02 '17 at 02:09
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    But it's completely useless for devs, for most folks I know firebug was the only reason to use Firefox, now Chrome's default tools are better, which is a sad time indeed. Some seriously basic functionality is missing from dev tools. Without that level of granularity mavens stop using the browser and stop promoting it to friends, colleagues and clients. Firefox uptake stats are in the bin as a result. – BradZoob May 12 '17 at 03:55
  • There is a bug collecting all [Firebug features missing in the DevTools](https://bugzilla.mozilla.org/show_bug.cgi?id=991806) and another one [prioritizing the most pressing ones](https://bugzilla.mozilla.org/show_bug.cgi?id=1267303). I suggest you vote on the ones you're missing most and/or add your comments there and file a new bug blocking bug 991806 if your feature is not listed in the "Depends on" list. And as their [code is open source](https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Source_Code/Mercurial), you can even help them fixing those bugs. – Sebastian Zartner May 12 '17 at 05:36
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    This is a sad day indeed. Bye firebug – pokeybit Jul 27 '17 at 13:13
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In 2 steps:

  1. disable or (better) uninstall Firebug
  2. press F12 and enjoy the console and other Devtools

Why: Firebug is not regularly updated anymore, it often becomes obsolete with new FF update. Tools already available in Firefox (F12) are inglobating it.

fresko
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