This document explains all of the settings available in Mozilla Firefox for controlling pop-ups.
Pop-up windows, or pop-ups, are windows that appear automatically without your permission. They vary in size but usually don't cover the whole screen. Some pop-ups open on top of the current Firefox window, while others appear underneath Firefox (pop-unders).
Firefox allows you to control both pop-ups and pop-unders through the Content panel in the OptionsPreferences window. Pop-up blocking is turned on by default, so you don't have to worry about enabling it to prevent pop-ups from appearing in Firefox.
When blocking a pop-up, Firefox displays an information bar (if it hasn’t been previously dismissed – see below), as well as an icon in the location bar.
When you click either the OptionsPreferences button in the info bar or the icon in the location bar, a menu is displayed with the following choices:
To access the pop-up blocker settings:
The pop-up may not actually be coming from Firefox. You can determine where the pop-up is coming from by the appearance of the window.
Certain events, such as clicking or pressing a key, can spawn pop-ups regardless of if the pop-up blocker is on. This is intentional, so that Firefox doesn't block pop-ups that websites need to work.
Sometimes ads are designed to look like windows, but really aren't. Firefox's pop-up blocker can't stop these ads.
When you visit a Mozilla website, sometimes you'll see a pop-up asking you to participate in a survey. The only third-party that Mozilla ever uses for surveys is SurveyGizmo, which has been vetted by our legal and privacy teams. The Firefox pop-up blocker doesn't block these pop-ups.