Firebug says "No Javascript on this page", even though JavaScript does exist on the page

Question

Why does Firebug say there is No Javascript on this page when there are clearly loads of JavaScript on the page. I even reloaded the page several time to make sure but it still show the same message.

It never used to do that before, but all of a sudden it misbehaves.

Is it because of some configuration issues or because of something else?

Solution 1

As of Firefox version 50, it seems that Firebug will no longer work as Mozilla are migrating to Firefox Devtools. The tab Tools/Web Developer has a 'debugger' option. See this page for a discussion on the migration. Read all the posts dated 19 November for further information.

It seems to me that the option gives less functionality but Firebug per se is never going to be fixed for Firefox 50 and beyond

Solution 2

EDIT 2017 April

This answer is now outdated and I'm not even testing it anymore because I'm no longer using Firebug (a shame, I loved it years ago in a time it was The tool of trade for web developing).

EDIT 2014 November

The original answer is now more than a year outdated due to firebug evolution. Thanks to @AmadeusDrZaius to keep it on tracks

Answer for outdated firebug versions For anyone still with this problem after updating Firebug. Just click Clear Activation List option inside the Firebug menu.

For those who can't find it, note that "Clear Activation List" shows up in the dropdown from the Firebug icon in the toolbar, but not the Tools > Web Developer > Firebug menu.

I guess due to the bug previous hitting your working page it stays listed as "no activate FB for this site please".

Solution 3

I encountered No Javascript on this page after upgrading Firefox to ver 50.0, with Firebug ver 2.0.18. I tried refreshing Firefox, even completely uninstall Firefox and installed again. Nothing works for me.

A couple of hours later, I downgraded Firefox to 49.0.2, and voila, it works right away. I downloaded the old version here.

Solution 4

I tried everything on this list and nothing worked for me except resetting Firefox like so:

https://support.mozilla.org/en-US/kb/reset-firefox-easily-fix-problems

Solution 5

I realize there are already 10 answers to this question, but in my case none of them helped. I'm running Firefox version 39.0 and Firebug version 2.0.11. The only fix is to completely restart Firefox (i.e. not just the tab or instance with the problem).

Perhaps it's due to Firefox's over-usage of memory, or maybe there's a bug in Firebug. I can't speak to that, but what I do know is it didn't work. I killed Firefox, opened the exact same page again with no changes made and now it works. This has happened to me numerous times and a complete restart always fixes it, but that's the only thing that does.

View more solutions

Comments

[AllTooSir]

Sometimes if there is a script error on the page the entire script compilation could fail and Firebug doesn't see the script.

[fflorent]

Could you provide a link for an example, please?

[NickT]

Bug has reappeared with Firefox 50 and Firebug 2.0.18

[Dan Stevens]

I've just restarted Firefox and I'm getting this on ever site I visit. I was in the middle of working on something too!

[NickT]

Damn!. My Ubuntu machine had version 49.0.2. Now without thinking I have just let it update to 50.0 as part of general housekeeping with 'Software Updater'. I can confirm that Firefox 50.0 and Firebug 2.0.18 doesn't work in Windows Vista and Ubuntu 16.04LTS

[Eaten by a Grue]

At the moment you can find v49.0.2 here: ftp.mozilla.org/pub/firefox/releases/49.0.2

[norwebian]

This works for me. That is, both the new tab technique and de-/reactivating. It seems pretty random when the problem appears, and to me it happens every now and then on domains for which I never activated Firebug. That case is somewhat complicated with redirection and authentication, but the external site does some kind of test and telling med that I do not have JS active, so I must press a button to proceed. Just thought I'd share my observations.

[East of Nowhere]

That option isn't in the Firebug menu, and isn't mentioned in that link getfirebug.com/wiki/index.php/Firebug_Menu anymore either.

[Liam]

This answer is outdated

[Chris Middleton]

For those who can't find it, note that "Clear Activation List" shows up in the dropdown from the Firebug icon in the toolbar, but not the Tools > Web Developer > Firebug menu.

[caramba]

+1 cause this helped! side note: after resetting all my add-ons where gone

[Pointy]

There no longer seems to be a "Clear Activation List" option in the Firebug menu (I'm on version 2.0.6). However the plugin still seems to find itself in the same broken situation sometimes. (I've looked in the menu from both the toolbar and from the Firebug panel; it's not present in either location.)

[jean]

I'm using FF 30.1.1 Firebug 2.0.6. The "Clear Activation List" option is the last option from the dropdown on the Firebug icon from the Firefox bar (not the firebug bar)

[naitsirch]

I have inserted a screenshot showing the button, which should be used.

[jean]

Thanks @naitsirch for the screenshot, strange thing only that option is not in german. I don't put one because my FF is not in english

[naitsirch]

Sorry for confusion @jean. Originally that option was in German, too ("Aktivitätsliste leeren"), but I have manipulated the screenshot, because most of the users here understand English but less people understand German ;-)

[csauvanet]

For me reopening the page in a new tab is enough, I can see the javascript again for a while.

[Chris Middleton]

@csauvanet +1 for your tip; opening a new tab was enough for me as well.

[Steve Cohen]

And losing and then reinstalling the firebug add-on may have helped! Who knows what version I used to have? A new version of FF was just installed in my case.

[Steve Cohen]

Actually, @Tom_Thomson's answer sits below now :-)

[Adam]

never had this before today, but suddenly it came. could it be connected to the fact that I let firefox update itself to version 50 shortly before? Tried this solution, also un-installed and re-installed firebug. No luck. Really don't want to have to reset the whole firefox

[Claus]

Wow you're a lifesaver. Struggled for a couple of hours trying to learn the FireFox Developer Tools a knockoff of the Chrome debugger. Has some nice features, but did not like the fact I could not use FirePHP and also I noticed I could not get directly to eventListeners when I used querySelector. Used your link to get the old version back and like you said "voila"

[kiatng]

Yeah, I tried the alternatives developer tools in Chrome, MS Edge, IE, Firefox Developer Edition, but didn't like any of them. After installing the older version, don't forget to disable the auto-update by opening the Menu, select Options, click Advanced and then click the Updates tab.

[NickT]

Well done @kiatng - On my Windows Firefox 50 - no scripts work. On my Ubuntu 49.0.2 Firefox all is well. I hope they fix it for version 500 soon.

[David Newcomb]

Thanks for updating us here, much appreciated.

[Steve Hibbert]

This should be the answer now, Firebug is dead.

[CJ Dennis]

According to blog.mozilla.org/futurereleases/2016/02/04/… Firefox 50.0.1 will be released on 2016-12-13, so it's a bit of a wait to see if they fix it.

[raiz media]

Lifesaver! This was a real pain; I was wasting lots of time trying to figure this out, until I read your post. Ths should be the TOP answer!

[freefaller]

RIP Firebug :-(

[McHat]

:( :( :( :( :( :(

[zoonman]

New Firefox devtools have Firebug theme which is much better than default one.

[TheTrueTDF]

That's it I'm quitting the web :D

[jahu]

I'm afraid the problem is here to stay. Firebug doesn't seem to work right with Firefox 50 and is likely never to be fixed.

[Johnny Wong]

Have briefly tried DevTools. Thinks that UI & feature set of DevTools is quite non-competitive with Firebug (e.g. for DevTools, javascript files list display like "...924821a54aacceb1870d07.js" VS Firebug's fullpath selection combobox; Cannot find "break on mutate"). User-friendly Firebug & Tab Groups are the main reasons I like using Firefox. Seeing they are becoming less User-friendly & good-looking than before, Mozilla will surely lost some real fans according to their decisions.

[Gi1ber7]

I used the "Clear Activation List" option. But still have the same error.

[Kevin Parker]

Is there a version of Firefox Dev Tools for standard firefox? I'm not about to use 2 firefoxes one for our website and one for writing. Why the F they would do this, I hear the masses... They're yelling Chrome!

[l00k]

Not enough.. There is no event inspection on DOM element - main reason why I don't use build-in inspector.

[PhoneixS]

To be mention is that Firebug didn't disappear, it has just been merged with DevTools and now it's shipped as part of it under the name Firebug.next (or firebug 3).

[Sanchit Khera]

This worked for me. It simply deletes everything form the browser. So I had to again install firebug plugin.

[Lucky]

Outdated answer.

[Pino]

The 49.0.2 installer dies silently on my machine unless I select "Run as Administrator" from the context menu of resource explorer.

[user14471901]

Well that is a real shame. Discovered this mess after having been focused on IE11 debugging, and retested in Firefox for the first time in a while and 'what the'. If the Firefox internal debugger wasn't so clunky (change some about:config stuff, restart, just to enable; then mouse over variables are SOOOO slow to show values, and highlighting of breakpoints, breakpoints lists whats that about) I could get used to it, but the tool built in is a bit janky. No good feature lives unpunished by its overlords forever I guess.