Firefox comes with a built-in popup blocker. It is much better than external popup stoppers, as it can differentiate between user-requested and unrequested popups. But, yesterday I saw occasional popups when surfing using Firefox. It turns out that some clever people figured out that you could launch popups from Flash, getting around the Firefox default settings.
But, you can have solutions using following steps:
1. Type about:config into the Firefox location bar.
2. Right-click on the page and select New and then Integer.
3. Name it privacy.popups.disable_from_plugins
4. Set the value to 2.
The possible values are:
* 0: Allow all popups from plugins.
* 1: Allow popups, but limit them to dom.popup_maximum.
* 2: Block popups from plugins.
* 3: Block popups from plugins, even on whitelisted sites.