Tap here to go to the mobile version of the site.
Your Firefox is out of date and may contain a security risk! Upgrade Firefox

Support Forum

Firefox hanging because of Javascript


In the last few weeks, a lot of my Firefox windows hang for long periods of time - a minute or more. Today it got much worse, where it would hang for ever (defined as many minutes until I got tired of waiting and killed it).

After trying many things - It appears to be Javascript related. If I disable javascript - all the sites I go to first complain that javascript is not enabled butthen offer me a javascript free version. I have no hangs with java script disabled. a few sites just won't work with out it - but still no hang. As soon as I re-enable javascript - all my windows hang. I have tried only having a couple tabs open but still they hang. This happens with google mail and Yahoo mail as my base two. But if I open several other windows instead, they hang as well.

I tried downgrading to Firefox 17 - no help there.

I tried updating flash, I tried downgrading flash. No difference.

I have run out of ideas on what to do here.

Additional System Details

Installed Plug-ins

  • Adobe PDF Plug-In For Firefox and Netscape 10.1.5
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
  • Next Generation Java Plug-in 1.6.0_38 for Mozilla browsers
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • Microsoft Lync 2010 Meeting Join Plug-in
  • ActiveTouch General Plugin Container Version 105
  • 4.1.10329.0


  • User Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/17.0 Firefox/17.0

More Information

Tyler Downer
  • Administrator
  • Moderator
1165 solutions 6641 answers

The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions, Open websites, and some Preferences.

To Reset Firefox do the following:

  1. Go to Firefox > Help > Troubleshooting Information.
  2. Click the "Reset Firefox" button.
  3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
  4. Firefox will open with all factory defaults applied.

Further information can be found in the Reset Firefox – easily fix most problems article.

Did this fix your problems? Please report back to us!

Question owner

Thanks for your rreply. I should have mentioned that I tried that step already as well. No help from that either.


Question owner

I've temporarilly given up on Firefox. It has become completely unusable on any web site at all.

All these sites work fine in IE - but I use IE for other purposes. So - I installed Safari and important all my bookmarks from FF. All sites work quite well in Safari.

Its too bad - I have liked Firefox for years. But its been getting a little frustrating with rapid updates and now this issue just killed it for me. No idea what is happening on my install of FF as it does not appear to be a widespread issue.

telecomguy 0 solutions 1 answers

I've been having the same issue, and it started yesterday. FF18 worked fine during the day, I shut down my laptop (work laptop) and took it home at the end of my work day. When I booted up, Windows 7 finished configuring whatever updates they pushed. As soon as I launched Firefox and attempted to go to a site that had javascript on it, the browser would lock up.

I've attempted to start FF in Safe mode, no dice. New profile, no dice. If I disable javascript, pages load without problems but of course the part of the page that requires javascript won't load.

It's pretty frustrating because the only other browser I can use on my work laptop is IE, which has no where near the amount of extensions that Firefox does.

Modified by telecomguy

dc1313 0 solutions 2 answers

This is also happening to me and has been for about a week and half. Its really annoying.

  • I have windows 7 ultimate 64bit
  • I have firefox 18.0.2
  • I have cleared everything, cache, cookies, history, etc..
  • I have reset firefox
  • I have java version 7 13
  • I have 8 gig of ram
  • javascript is turned on.

Some "submit" buttons and some links are not working and it displays this in the lower left corner: javascript:;

any help would be appreciated. thank you.

Modified by dc1313

Digihotaru 0 solutions 1 answers

Very same issue here. I've tried resetting, starting in safe mode, and deleting then creating a new profile. Nothing works. Uninstalling / re-installing helped for a few hours, then the same behavior again.

Win 8 Pro x64 Seeing the exact same behavior on both my desktop and my laptop.

thbjr 0 solutions 2 answers

I did have this problem. Several blog webpages I went to would hang up my computer for about a minute. Spent hours troubleshooting. Same issue with the javascript option. Finally I noticed that all the hanging webpages had something in common, they had DISQUS powered comments section at the bottom of these blogs. Having AdBlock Plus installed on Firefox, I did a right click on the comment section and selected 'Adblock Plus: Block image' from the menu. Then I selected disqus.com under 'Blocking filter'. Now all these webpages will load without freezing up my computer. I can't see the comment section any more, but am willing to sacrifice comments to prevent this problem. Maybe Firefox might look into this to possibly fix this bug.

Question owner

it may be that this disabling of comments works but I use comments and frankly I'm tired of trying to fix Firefox Bugs.

I just ended up moving to Chrome (safari had different issues). No more issues at all with chrome. I should point out that Firefox works fine on several other laptops. But my work laptop will not work with it.

skysentinel 0 solutions 1 answers

I'm having the same issue, have tried the above suggested fixes, and they categorically do not work. There is a fundamental flaw in Firefox, regarding JavaScript, and it has existed for months. Too bad that no one is taking this problem seriously, because, at this writing, I am giving up, after years of being a Firefox user.

thbjr 0 solutions 2 answers

Resetting Firefox does absolutely nothing! Disabling add-ons does nothing! Uninstalling all add-ons does nothing. Uninstalling Firefox and all user files does nothing! All fixes that Firefox list does absolutely nothing to fix this issue, except to waste hours of Firefox users time! In researching this problem, I've seen post going back 3 or more years with people having problems with Firefox freezing. Endless new update versions of Firefox seem to come out every few weeks and just keeps passing the bug on down with no fix! When is Firefox finally going to do address this problem and do something to fix the bug instead of leaving upon their users to do?

Question owner

I think the part that makes this both frustrating and intriguing is the fact that the issue appears to be machine dependent. For me - this only happens on my work laptop. On my home laptops - FireFox works perfectly fine. So - the Javascript issue is real - but it is clearly also tied to something else that is machine dependent.

As I said - I have given up completely on Firefox on my work machine. Even if they fix it - I will not be returning to FireFox as I refuse to waste any more time even trying it any more. And at the first sign of trouble on my home laptops - I will dump Firefox without a moments thought and move to Chrome - which works perfectly well on all my laptops including my work one. The only minor thing that Firefox does better is the simple use of bookmark management. I am not a fan of how Chrome displays their bookmarks as they are not quite as user friendly. But all things considered - its minor and the tool works much faster.

fbpat 0 solutions 4 answers

Turning Javascript off makes firefox work like normal. Other browsers have no issue. This started acting up on me about 4-5 days ago. Quite annoying to not be able to run firefox with javascript on. Is there a way to reinstall javascript?

I have tried safe mode, resetting firefox, reinstalling firefox, disabling addons, changing profiles, it really comes down to javascript being turned off fixes it for me. So despite being fairly computer savvy, I have no idea what is causing this. I ran Microsoft security essentials, a few malware/spyware utilities, checked hijackthis. I cannot find the issue. Firefox likely submitted 50+ crash reports.

Modified by fbpat

  • Top 10 Contributor
  • Moderator
3197 solutions 24404 answers


Please ask a new question - https://support.mozilla.org/en-US/questions/new - and provide the requested information.

Also open about:crashes in the URL bar and hit Enter. Please load the most recent crash reports and see what was reported. If you need help interpreting those crash reports, please submit those report ID's to this forum and one of us can look at them.

  • Top 10 Contributor
  • Moderator
3197 solutions 24404 answers

locking this thread due to age - plus it's gone off-topic - hanging vs. crashing