Fix Firefox "Unresponsive Script" warnings...

Posted by Dan on Jul 7, 2006 @ 1:53 PM

I've run into this problem from time-to-time. I think the main time I run into the problem is when uploading files to a server, where the form submit is triggered by JavaScript—although I haven't dug around enough to confirm if this is the case or not. Anyway, here's a way to increase the default timeout.

The dom.max_script_run_time is an integer that is the number of seconds to wait before prompting that a script is taking too long to respond. I found this information over at Itchy Hands.

Ever since I upgraded to Firefox 1.5, I’ve been getting some unresponsive script warnings on sites that employ heavy Javascript like Gmail or Bloglines. Curious about it, I dug around and managed to find out how to fix the problem.

Firefox unresponsive script dialog

To fix it, you’ll need to access the hidden configuration page in Firefox. Just type about:config in the address bar and you’ll get a page full of hidden configurations which you can tweak till your heart’s delight.

In the 'Filter' box, type dom.max_script_run_time. This will narrow the options till only the dom.max_script_run_time option remains. Right-click it and choose Modify. A box pops up. Change the number to something bigger like 20. This is the maximum time a script can run before Firefox considers it 'unresponsive'.

If you can’t find the string in the about:config page, create it by right-clicking anywhere and then choose New—> Integer and enter dom.max_script_run_time. When prompted for the value, use 20.

So far I’ve not had anymore unresponsive script warnings, so I guessed that fixed that problem! However some extensions may also cause similar problems. Hope this helps.

Categories: JavaScript, qForms, HTML/ColdFusion


  • Thanks - I was annoyed when I added certain modules to my personalized Google homepage.
  • Itchy Hands, Thanks so much for the fix on script errors in FireFox. It was so fast following your instructions! I appreciate the time you took to help with this annoyance!
  • Thank you sir. helped alot. lotus notes domino on a semi slow connection timed out alot.
  • Thanks for pointing this out. It has made using Firefox on JS heavy site's "usable" on my slow old 400Mhz G4. Cheers.
  • DUDE! You saved me from literally throwing coffe cups in my house!
  • I get script errors on lines 1,6,and 8 when I boot up. Normally when yahoo messenger is loading and when icq is loading. I'm using firefox 2.0. would I use the fix described above for this?

    thank you
  • unfortunately it doesn't work for me :(
  • Get the updated version of the Firefox add-on called Google Calendar Quick Add. Earlier versions of the add-on caused this error.
  • You can find further suggestions for fixing the problem at at
  • Thank you!! I know it's been ages since this was posted but it helped fix the problem I have been having. My computer was basically not functioning because of the script errors, now I have no problems at all :D
  • Anti Firefox Virus

    I need some feedback from other Firefox users on the Comcast access to internet.

    Ive picked up some kind of disabling virus which prevent Firefox from reaching ANY servers, and I dont know how to get rid of it.


  • It didn't help for me.....
  • May 4, 2008 Used these instructions to adjust my browser. Had been getting unresponsive script notice each time I posted at Wordpress. So far I’ve not had anymore unresponsive script warnings, so I guessed that fixed the problem! These instructions work just as well for Firefox/
  • i tried doing the about:config...... but still im having unresponsive script warnings.... i hate it! what else can i do? please help me. tnx.
  • DUDE!...It worked! Thank you for saving me from having a stroke! You are the best...I am bookmarking you!
  • I have the same problem after Firefox update. Changing time does not help. Is there any way to identify wich program that causes this? Otherwise it´s goodbye firefox and welcome safari.
  • This just doesn't wooooooooork :(

    I have seen this "fix" posted so many places but it doesn't help at all. First it affected Firefox, tried to fix it for over a week, gave up. Started using IE for Facebook, worked fine, then the next day, same problem. I can't comment, view photo's, view my own page, view messages nothing. I have tried back dating firefox 4 times from version 3.6 to version 3.5 8 to 3.5 1 3.0 18 and they're all the same.

    This problem has been going on for over a year now and there is no definitive fix for this yet. The worse thing is, I haven't done anything. I made no changes for facebook to stop working. One day it worked, the next nothing. Same story with IE. And i mean NOTHING, no changes whatsoever.
  • i wish i googled this earlier. not seeing that stupid non responsive script box.
  • Wow, I have been fighting this for a long time, got no relief from firefox solutions. This has saved me from pulling out what little hair I have left. Thank you.
  • I'm not a techie at all and stumbled onto this article. It's been an hour and so far so good!

    Bladie marvelous!
  •'re the MAN! Thx!
  • Woot! Thank you so much! This really helps a lot XD
  • That was so helpful man! I've just done that and my browser is hanging no more
  • didn't work for me either.
  • I don`t get it....I am here to find out how to get the "unresponsive"
    box to pop up SOONER. In my case it shows up when I`m getting
    "Firefox is not responding" parenthetically on very top line on the screen.
    As soon as the "Stop script" box shows up and I hit "Stop" the system
    starts to run normally again ( about 90% of the time ). Isn`t the box showing
    up a good thing ??
  • AngryCornflakes's Gravatar
    Thanks buddy i tried it hope it works
  • I have never known if the message was good, bad or indifferent; it is annoying but if it is keeping something bad from happening that is a good thing....HMMM
    usually I stop the script and reload the page which allows me to continue but I would like to know if letting the script continue is in any way harmful and if there are other options.
  • I've found that disabling Java tends to make the computer work quicker, but most programs I use run on Java, so I have to give your tip a chance. I'm using FF 3.6 btw.
  • Fantastic! Worked Perfectly!! Super easy instructions and immediate fix! thank you, thank you, thank you... it was driving me NUTS!
  • Wow! Easy!! Now to see if it works!! THANKS!
  • This isn't a fix. You're sweeping the problem under the metaphorical rug. This might even cause problems because you can't stop unresponsive scripts, because you have no idea what's causing the browser freeze.
  • @Gaara:

    While for some issues it's certainly not a fix, for my use case in FF1.5 it was. I had an internal app that was just process process intensive. The JS engine was much slower than I the unresponsive script dialog was causing problems and adjusting the behavior was the only fix.

    I agree that this largely can just mask a problem though. However, Firefox has improved so much in JS performance that user's who are running the latest version of Firefox (and everyone should be) shouldn't see issues.
  • Fabulous! I've done it, and feel confident it will help a lot!
  • Whenever I opened a tab for my local newspaper I would get the 'unresponsive script' message due to the amount of flash advertising on the site. I first changed the settings to 20, but although this improved performance, occasionlly I still got the dreaded message. So I have now set it at 40 and everything seems fine
  • Still getting this problem constantly. Updated Firefox today and it got even worse. Is it possible to stroke out from frustration? I'm running adblockplus and no other addons..

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