To answer need you to be a little clearer Bernadine.

That message from website may be triggered by other add-ons or by bad script on the website that throws that message.

Try Firefox Safe Mode to see if the problem goes away. Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

• On Windows you can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
• On Mac you can open Firefox 4.0+ in Safe Mode by holding the option key while starting Firefox.
• On Linux you can open Firefox 4.0+ in Safe Mode by quitting Firefox and then going to your Terminal and running: firefox -safe-mode (you may need to specify the Firefox installation path e.g. /usr/lib/firefox)
• Or open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Once you get the pop-up, just select "'Start in Safe Mode"

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one. Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.

Firefox's internal JavaScript switch has only two settings: on and off. If JavaScript works on some sites and not others, then your switch is "on" and you can run down other potential culprits.

Ed's suggestion is a great place to start. If you aren't sure about your extensions and want more specific comments, you can extract the list from the Troubleshooting page. Either:

• Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the upper left corner, click the "Copy text to clipboard" button. When pasting into a reply, you can delete the part from Important Modified Preferences to the end.

Thanks for the answers. It only happen once in a while so I'll keep your answers and if/when it happens again, I will try your suggestions.

So I guess this can be closed and if/when I encounter the problem, I can try the solutions and if they don't work, I'll write again.

Thanks, Bernadine