Firebug says “No Javascript on this page”, even th

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?

Answer 1

Well Firefox native Inspector is good... I know that you will miss some things, but in general we can survive with it. The good news is... less one addon, FF will be faster :)

Answer 2

Since Firefox 49.0 and Firebug 2.0.18 the Script panel is broken. This is due to some internal Firefox API changes. And because Firebug is officially discontinued, this unfortunately won't get fixed anymore.

There was also a bug in Firebug 2.0.11 (and below) in combination with Firefox 39.0 causing this problem. This bug is filed as issue 7918.
It happens when the Script panel is enabled and you close Firebug and reopen it.

You can see two related error messages logged to the Browser Console (can be opened via Ctrl+Shift+J or Firebug menu > Developer > Browser Console):

error occurred while processing 'attach: TypeError: docShell is null Stack: getChildDocShells@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/webbrowser.js:53:7 ...

and

onPacket threw an exception: Error: Server did not specify an actor, dropping packet: {"error":"unknownError","message":"error occurred while processing 'attach: TypeError: docShell is null\nStack: getChildDocShells@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/webbrowser.js:53:7 ...

Solution:

The only solution until this bug is fixed is to restart Firefox completely.

Answer 3

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.

Answer 4

One time this caught me out was when I published one of my sites and I was checking it out. No Javascript was working, there were no errors in the console and firebug showed no scripts.

It turned out that in that instance, I'd forgotten to allow the site in NoScript - so there really were no scripts being loaded.

Not sure if that's the problem you're facing but it's worth being aware of.

Answer 5

FWIW this problem is still happening in August 2016. I'm using Firebug 2.0.17 with Firefox Dev Edition 50.0a2.

As a workaround, I'm able to use the Developer Tools, though they are not as robust as Firebug (when it's working).