Pop-up blocker settings, exceptions and troubleshooting

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  • Creator: Tonnes
  • Comment: remove period after (close)optionspreferences template
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  • Reviewed by: ideato
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This document explains all of the settings available in Mozilla Firefox for controlling pop-ups.

What are 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 pop-up-icon-win pop-up-icon-mac Popup-blocked.png in the location bar.

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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:

  • Allow/Block pop-ups for this site
  • Edit Pop-up Blocker OptionsPreferences
  • Don't show info bar when pop-ups are blockedDon't show this message when pop-ups are blocked
  • (show the blocked pop-up)
Blocking pop-ups may interfere with some websites: Some websites, including some banking sites, use pop-ups for important features. Blocking all pop-ups disables such features. To allow specific websites to use pop-ups, while blocking all others, you can add specific websites to the list of allowed sites.
Blocking pop-ups doesn't always work: Although Firefox blocks most pop-ups, some websites may show pop-ups using uncovered methods, even when blocked.

Pop-up blocker settings

To access the pop-up blocker settings:

  1. Click the menu button New Fx Menu Fx57Menu and choose Options.Preferences.
  2. Select the Content panel.

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    Content Popup Win7 Fx23
    Block popups Mac Fx 23 Block popups Linux Fx 23

In the content panel:

  • Block pop-up windows: Uncheck this to disable the pop-up blocker altogether.
  • Exceptions: This is a list of sites that you want to allow to display pop-ups.


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    The dialog has the following choices:
    • Allow: Click this to add a website to the exceptions list.
    • Remove Site: Click this to remove a website from the exceptions list.
    • Remove All Sites: Click this to remove all of the websites in the exceptions list.
Note: Blocking pop-ups may not always work and may interfere with some websites. For more information, see the What are Pop-ups? section above.

Pop-ups not being blocked

Is the pop-up coming from Firefox?

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.

  • If you see the location bar with the little bookmark star in the pop-up window, the pop-up is coming from Firefox. Another good indication is the Firefox logo or the orange Firefox button on Windows 7 in the top left corner of the windowAnother good indication on Linux is if you see the text "- Mozilla Firefox" at the end of the title bar.
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Is the pop-up blocker on and enabled for this site?

  1. Click the menu button New Fx Menu Fx57Menu and choose Options.Preferences.
  2. Select the Content panel.
  3. Make sure the Block pop-up windows checkbox is checked.
  4. To the right of Block pop-up windows, click the Exceptions... button. A dialog will appear that shows all the sites that are allowed to show pop-ups.
  5. If the site that's opening pop-ups is in the list, select it and press Remove Site.
  6. Click CloseClose the Allowed Sites - Pop-ups window.
  7. Close the about:preferences page. Any changes you've made will automatically be saved.

Is the pop-up shown after a mouse click or a key press?

Certain events, such as clicking or pressing a key, can spawn pop-ups regardless of if the pop-up blocker is on. This is so that Firefox doesn't block pop-ups that websites need to work.

Is it a true pop-up window?

Sometimes ads are designed to look like windows, but really aren't. Firefox's pop-up blocker can't stop these ads.

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