Sometimes the website will show an alert box akin to "Are you sure you want to leave?" when you try to leave the site.

Is it possible to disable this from happening, without using something like the NoScript extension?

3 Answers 3


Tools > Page Info [Permissions] will let you set the permissions for a particular page/site.

On the Open Pop-up Windows setting, clear the "Use Default" check-box, and set Block

If that's not enough, you may be able to use a GreaseMonkey script, but without knowing which web-site, no-one here will be able to tell you how.


Not limited to Firefox, with ClickOff you can get rid of any annoying popup, on a Windows system.

  • I'm running Ubuntu
    – Hayek
    Feb 4, 2010 at 4:51
  • ahh, sorry you should add this bit of information to your question :)
    – Molly7244
    Feb 4, 2010 at 12:46
  • My mistake. I added it as tags but not in the post itself.
    – Hayek
    Feb 5, 2010 at 0:31
  • @Rajje - no, you didn't ... twas me editing the tags for you. :) Anyway, i'll leave the answer there in case someone stumbles over this question.
    – Molly7244
    Feb 5, 2010 at 0:59

This answer is really late, but this question showed up in Google for me when I was looking for a solution to this problem today. The solution I eventually found is here: http://userscripts.org/scripts/show/23865

// ==UserScript==
// @name           BlockUnloadEvents
// @namespace      http://theaceoffire.8k.com/STOPTHEMADDNESS
// @description    This stops ANY AND ALL javascript that stops you from leaving a page. Inspired by this greasemonky script: http://userscripts.org/scripts/show/20781
// @include        *
// ==/UserScript==
(function() {
      unsafeWindow.onbeforeunload = null;

      unsafeWindow.onunload = null;

      //unsafeWindow.alert = null;

      //unsafeWindow.confirm = null;

      //unsafeWindow.prompt = null;

      //unsafeWindow.open = null;  

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