I get repeated error messages about there being a problem with Java Script when visiting various web sites

Question

The message pops up repeatedly at various web sites and I can x it out and eventually they will stop but when I goe to a different page in that web site, this occurs again. The message is as follows "Error:Document.get elements by Tag Name (""head") [0] is undefined

Answer 1

Hi,
Try the Firefox Safe Mode''' to see how it works there. The Safe Mode is a troubleshooting mode, which disables most add-ons.''
''(If you're not using it, switch to the Default theme.)''
* You can open the Firefox 4.0+ Safe Mode by holding the '''Shift''' key when you use the Firefox desktop or Start menu shortcut.
* Or use the Help menu item and click on the '''Restart with Add-ons Disabled...''' menu item while Firefox is running.
Choose to [https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode#w_safe-mode-window_2 Start in Safe Mode].
To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before using the Firefox shortcut (without the Shift key) to open it again.
If it is good in the Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one.
Please follow the [[Troubleshooting extensions and themes]] article for that.
''When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.''
Alternatively you may also want to Reset Firefox and start afresh.
The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information.
Note: ''This will cause you to lose any Extensions, Open websites, and some Preferences.''
To Reset Firefox do the following:
#Go to Firefox > Help > Troubleshooting Information.
#Click the "Reset Firefox" button.
#Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
#Firefox will open with all factory defaults applied.
Further information can be found in the [[Reset Firefox – easily fix most problems]] article.
Did this fix your problems? Please report back to us!'''