window.open(); is not ignored altogether — otherwise harmless pop-ups would be blocked — but it's only honored when triggered by certain events¹, like clicking a link or submitting a form. Pop-ups shouldn't open without any action on your part.

Make sure the "Block pop-up windows" option is checked, and that the site is not on the Exceptions list.

• Pop-up blocker settings, exceptions and troubleshooting

If the problem persists, check if the issue occurs when you start Firefox in Safe Mode.

• Diagnose Firefox issues using Troubleshoot Mode

¹ change click dblclick mouseup reset submit

Popup blocker is on because as I said, when I click the back button on that site, the popup window gets blocked. So there's no exceptions for that site either.

Which leaves us with my previous question:

If the problem persists, check if the issue occurs when you start Firefox in Safe Mode.

• Diagnose Firefox issues using Troubleshoot Mode

Restart in Safe Mode then back to Normal Mode and once again popups are being blocked. That was really odd.

Go to the Firefox add-ons web page; https://addons.mozilla.org/en-US/firefox/ Search for pop-up or add blockers.

Adblock Plus could indeed help. That is what I use to block ad popups with just a right click.

Another neat addin is "request policy" . Back to using this and will try to see if it gives any relief. I will report back later. All this happened to me after upgrading to Firefox 22 so i might go back to version 21. Didn't have the problem until the upgrade.

Well changing the about:config didn't work, but so far the "request policy" addin is working just great. Don't allow or give the site permission and the popups are stopped. Some sites you may have to allow because of content but the majority you don't. My popups are gone. Hopefully this changes in version 23 but until my popups are gone for now. Have a look at it and see if it would be suitable for you. Geat addin.

T

There are quite a few "extensions" (all ending in 's') but none followed by "tbutton.block.popups;" true or false.

With every mouse click I get a window with the message, "Firefox prevented this page from automatically redirecting to another page" but it doesn't prevent the popup. In addition, forums that I visit are peppered with orange highlighted and underlined words that have become links to spam messages. To see if this was a malware issue on my PC, I opened IE and was blessedly free of this maddening phenomena.

This became an issue with the last update. Also, the image loader simply shows the image in isolation and when you use the back arrow, this reply window is empty (having experienced this once, I saved this reply to my clipboard).

The person who asked this question has already chosen a solution, and your problems are unrelated. Ask a new question instead of continuing to reply here.

TonyNemo wrote:

There are quite a few "extensions" (all ending in 's') but none followed by "tbutton.block.popups;" true or false. 

Preferences whose names begin with extensions. belong to extensions (which are a type of add-on). You're not going to find them if you don't have the respective add-on installed. Specifically, preferences beginning with extensions.tbutton. belong to the Toolbar Buttons add-on.

TonyNemo wrote:

With every mouse click I get a window with the message, "Firefox prevented this page from automatically redirecting to another page" but it doesn't prevent the popup.

That has nothing to do with pop-ups. It's an accessibility feature that's disabled by default. Though if you're getting the message on every single link, something is wrong. Turn it off under Options - Advanced - General: "Warn me when websites try to redirect or reload the page".

• Advanced panel - Accessibility, browsing, network, updates, and other advanced settings in Firefox

TonyNemo wrote:

In addition, forums that I visit are peppered with orange highlighted and underlined words that have become links to spam messages.

These are usually just regular ads, which you can get rid of with Adblock Plus. If you don't get them in Internet Explorer, then you could have an ad-blocking solution there that you don't have in Firefox, or the ads could be inserted by a Firefox add-on.
To check your computer for malware, install, update then perform a full system scan with MalwareBytes' Antimalware.

TonyNemo wrote:

Also, the image loader simply shows the image in isolation and when you use the back arrow, this reply window is empty (having experienced this once, I saved this reply to my clipboard).

Use the Reset Firefox feature. Verify that the problems have disappeared before beginning to reinstall any add-ons.

• Refresh Firefox - reset add-ons and settings

Reset Firefox eliminated both problems.

You need to learn this tutorial: http://www.ghacks.net/2013/05/27/how-to-block-mouse-click-popups-in-firefox/

I'll certainly refer to it in future but resetting Firefox not only eliminated popups but now (for some reason) links in Thunderbird are opened rapidly in Firefox where there had formerly been a delay.

I just discovered this string. I am having pop-ups opening as well. The blocker is on but they still open up. I did a Firefox reset and it didn't help. I was just on a site and a window opens up for lowermybills.com. At the same time, Firefox told me that it prevented this site from opening a pop-up window.

Obviously something isn't working. Can anyone help?

I was having similar problems with popups dropdowns and whole new windows opening. I ran all the malware and rootkit tools. I did a Firefox reset. When I went to the addons page extensions right after the reset I noted an addon titled Linkcsicle. I removed Linksickle from the extensions. I then went to Control Panel, Programs and features and removed Linksickle. It gets installed when doing a download of other programs. It won't be identified as a malware, virus, etc. except that it bypasses Firefox adblock, popup blockers. Once I removed Linksickle as an add-on and from Windows 8.1 as a program, the pop-ups and unwanted new windows problem went away.