Warning Unresponsive Script in Firefox

Martin Brinkmann
Feb 18, 2008
Updated • Feb 10, 2013

I have been encountering a warning in Firefox lately which notified me the that a script on the current website was unresponsive asking me if I wanted to stop or continue. That's a pretty vague warning and I was puzzled at first about the cause of it. The strange thing was that the website seemed to have loaded completely and that the warning was displayed despite of this.

There are two possible causes for the error. It could be caused by a Firefox add-on or by a website which uses faulty JavaScript code. It's actually pretty easy to discover the cause for the warning message. Users need to stop the script and access the Firefox Error Console using the shortcut Ctrl-Shift-J or with a click on Firefox > Web Developer > Error Console in the menu. The last error message there should hint at the cause of the error.

Generally speaking it is more likely that an extension is the cause if you encounter the error on several different websites while a warning on the same website points to a faulty JavaScript on that website instead. There are exemptions of course, for instance if you run an extension that modifies the behavior on a particular site for instance.

If you suspect that a script just needs a few more seconds to run you need to edit a setting in the Firefox config. Type about:config in the address bar and filter for the string dom.max_script_run_time. The default setting is 20 (seconds), just add a few more, raise it to 25 for instance or even more.

There are a couple of other options available to resolve script warnings in Firefox. You can for instance install an add-on like NoScript or YesScript to either block all or only select scripts from running in the browser. Note that this works well only if the script is not required for the site's functionality.

Another option to find out if extensions are causing the warning message is to run Firefox with all extensions disabled. You can do so with a click on Firefox > Help > Restart with Add-ons Disabled.


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  1. jay said on September 10, 2010 at 7:03 am

    i want something to be secure in net without having a antivirus program.

  2. Ankit said on June 25, 2009 at 1:21 pm


    I tried using the above help,, but failed coz me not a techie guy… found a much easy to understand help on a website,,, followed the steps and it was solved.


  3. michelle said on March 16, 2009 at 8:11 pm

    sorry, not being crass: buggered eg: busted

  4. michelle said on March 16, 2009 at 8:03 pm

    Kristy Try disabling dom.max_script_run_time in about:config by using 0 (zero). Although, I found the value 1 works best, it loads up the page straight away, I hit stop script and keep going. Putting in 1000 or 0 (I found) is too slow. If you try the same sites in Explorer you will have the same delay, I think it’s not a bad fix, saves sitting looking at a blank screen when the java on the site is buggered. version 3.0.7

  5. Kristie Brown said on November 17, 2008 at 3:43 pm

    I get this error when I try to open firefox. I have changed the script time but it does not fix the problem. What else should I try?


  6. joe said on August 20, 2008 at 1:51 pm

    I am beginning to HATE firefox. Soo many damn problems lately. They need to fix all these bugs or I am dumping it. I dont have time for this crap.

  7. Morganna said on May 8, 2008 at 1:37 am

    Hello Martin!

    Is there any way that I can get FireFox to automatically stop the scripts for me? I have a very slow PC and FireFox will freeze for up to 5 to 10 minutes while it waits to prompt me.
    I will greatly appreciate any help! Thank you for your time, Take care!

    Morganna. x

  8. Malih said on March 24, 2008 at 7:39 am

    how do you describe faulty javascript? my script (still in beta) sometimes do that, and i don’t know what actually caused it.

  9. TechPavan said on February 19, 2008 at 10:50 am

    I too have experienced a similar problem, but the snap shown by you is not the same of mine, I use ff and I get such an error when using yahoo mail beta and keep the page open for a long time, I just stop the script of running every time I get that and I will be fine… lemme try ur soln…

  10. Jawwad said on February 19, 2008 at 10:27 am

    Actually I have experienced it several times myself but was not completely sure of the cause.

  11. Kittycalbard said on February 19, 2008 at 8:45 am

    Thanks for telling us about how to check it & the workaround — the dialog should tell us such things in the first place, IMO. I’m an extension maniac, so I’ve seen the error plenty of times over the years, but usually can’t do much past troubleshooting-wise aside from ignoring it. :-p

    To the other person (Chris) commenting above me: I haven’t updated my F3 nightly for a while (oops) so can’t comment on it, but somehow I’m not surprised… I get the feeling that a lot of the stuff being changed for Firefox 3 isn’t for the better. :-/ Even in Firefox 2, though, I use Download Statusbar and/or All-In-One Sidebar to replace the manager itself, mixed with Drag de Go for telling it what to do with files and sometimes DownThemAll if I have a bunch of downloads to queue up.

  12. chris said on February 19, 2008 at 1:05 am

    im using firefox 3 beta and the download box doesn’t work as well.

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