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How do I stop the javascript debugger, console, and performance profiler from freezing during javascript execution so I can troubleshoot the slowdown?

  • 5 replies
  • 1 has this problem
  • 39 views
  • Last reply by jscher2000

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I'm trying to debug a userscript that seems to be going into an endless loop on just one certain page. The page freezes and never finishes drawing and the script never finishes running.

However, while it's in the loop, the debugger, console, and performance profiler all stop working, as if they're waiting for it to finish. Those are the tools I need to see what it's so busy doing that it never finishes... if they freeze, I have no way of troubleshooting. How do I get the developer tools not to freeze during script execution?

Modified by Zatukp

All Replies (5)

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Hello? Any other js developers out there trying to use Firefox?

Or do all the other developers know something I don't?

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You could try the Dev Tools forum:

https://discourse.mozilla.org/c/devtools

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Yeesh. The support forum is the wrong place to ask support questions? Oh, and now another place to sign in with another account. Apparently everything Mozilla does is as dysfunctional as their browser. It's like they're trying to make this as frustrating as possible.

Thanks for the tip.

Modified by Zatukp

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Ok, going to that forum is not a solution. The login form asks you for an email address, which you submit and wait for the email, which contains a link, which you click, which brings you to a page that asks you for an email address, which you submit and wait for the email, which contains a link, which you click, which brings you to a page that asks you for an email address...

This is a really terrible way to treat users looking for help. I am getting really fed up. Mozilla doesn't appear to have any idea how to make a working browser OR a working support forum.

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Hi Zatukp, I suggest using a Github account to sign in to the Mozilla Discourse boards.

Were you able to successfully debug the script in other browsers?

Do you want to share a link to the script and the page that causes it to spin to see whether Firefox's dev tools work better for support volunteers?

Could you test in a clean profile that contains only your userscript extension (Greasemonkey, Tampermonkey, or Violentmonkey):

New Profile Test

This takes about 3 minutes, plus the time to set up and test your script on the problem sites.

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

Click the "Create a New Profile" button, then click Next. Assign a name like Aug2019, ignore the option to relocate the profile folder, and click the Finish button.

After creating the profile, scroll down to it and click the Launch profile in new browser button.

Firefox should open a new window that looks like a brand new, uncustomized installation. (Your existing Firefox window(s) should not be affected.) Please ignore any tabs enticing you to connect to a Sync account or to activate extensions found on your system so we can get a clean test. Just do the minimum setup to test the script

Any improvement in a clean profile?

When you are done with the experiment, you can close the extra window without affecting your regular Firefox profile. (Aug2019 will remain available for future testing.)