Often these scam pages are promoted through ad networks. (I don't recommend using that method because the tab will come back during automatic crash recovery anyway.) Hopefully this will let you close problem pages without having to 'kill' Firefox in the Windows Task Manager. On these pages, the keyboard shortcut is essential. Some pages have a script that detects when you are moving the mouse pointer up toward the tab bar and takes action to show another dialog, or moves to full screen view to hide the toolbar area. Pressing the Esc key numerous times in a row can cancel the reload as well as the dialog. If you cancel this dialog, the page may reload and immediately show it again. (2) Authentication dialog (asks for username and password) Check that box and click OK to block further dialogs. After two or three appearances, Firefox should add a checkbox at the bottom of the dialog to stop the site from showing more alerts. If you cancel this dialog, it may reappear.

Try it after each action to see whether it is available yet. The 'key' (ha ha) is the keyboard shortcut for closing the current tab, which is Ctrl+w (or on Mac, Cmd+w).

There are a few common patterns to these annoying pages, and these are some techniques for closing them without having to take drastic measures. I'm going to re-post some old advice and you can let us know whether any of it helps: Hmm, this could be a scam popup from a website that wants you to pay them for cleaning services.

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