This add-on can stop such pages; '''[https://addons.mozilla.org/en-US/firefox/addon/disallow-script-button/ disallow Script Button]''' {web link} The Disallow Script button looks like a letter "M" and the title is the Minus Script, drag and drop the button on a toolbar. If the button is not displayed then nothing operates, except rules for plugins. ------- Another way out of the trap is to (force it if needed) '''Close Firefox.''' Wait about 20 seconds for Firefox to finish closing. Right click on the Firefox icon and select '''Open New Window.''' Sometimes this works. If it opens, close it by '''Menu > File > Exit.''' This will flush out that web page from the Session Store.