My logs show a lot of people visiting this site looking for advice on how to stop Firefox pop-ups and pop-unders, which seem to have increased in frequency lately. Here’s an interesting bit of inside information from Asa Dotzler of the Mozilla Organization:
A number of pundits and bloggers have been wondering aloud whether or not we’ll be able to keep up with the pop-up spammers now that more of them are focused on us. Well, we shipped 1.0 with the capability to block these pop-ups and pop-unders but we didn’t enable it because we were concerned about breaking legitimate uses. If you’d like to turn it on, it’s a fairly simple change — and would be absolutely trivial for us to enable once we determine whether or not lots of websites are depending on the feature.
Here are the specific configuration steps to take to turn on the capability to block pop-ups from plug-ins, according to Asa:
- Open your Firefox 1.0 or 1.0.1 browser.
- Type about:config in the address field and press Enter.
- Right-click in the resulting config page somewhere and click New, Integer.
- Type privacy.popups.disable_from_plugins in the New Integer Value dialog box and click OK.
- Type 2 in the Enter Integer Value dialog box and click OK.
That’s all you need to do. Note that there are three possible values allowed in this dialog box:
- 0: open allowed
- 1: the opened windows are treated as popups, but they’re allowed to open (Firefox limits the number of these types of popups)
- 2: the window is a popup, block it
If you try this and encounter problems, be sure to let Asa know.
Ed Bott 
You were the first link for me googling “firefox popups”.
Thanky!
I’ve been infuriated with a popup I’ve been recieving from z1.adserver.com. This has been my biggest peeve.
Also, it seems that usatoday.com has the Firefox popup think working overtime.
Atfer reciveing 2 popups in firefox i was shocked, But I don’t think i’ll be seeing them again for A LONG TIME! Thanks for the patch
THANK YOU,
I started getting heavy continuous popups when I made the mistake of updating my Yahoo Anti-Spyware and redownloading it. I tried contacting Yahoo and Firefox and received no help. Yahoo declared it wasn’t because they merged with Firefox, and stated that it had to do with my spyware, when knowing full well it wasn’t. Firefox refused to reply or give assistance.
THANK YOU so much, after installing your block I had only five popups and that was it. THANK YOU THANK YOU
Thanks Mate,
No more annoying popups Hooray — i will notify all everyone in my department about this — who knows it may even convince some to switch to Firefox for good.
Thanks from Australia
When I went to change that key I already found that it was set to 2 but I also noticed these keys
privacy.popups.firstTime [set tp true, I changed it to false]
privace.popuups.usecustom [set to true, I changed it to false]
This seems to have taken care of the problem.