1. Open Mozilla Firefox and press the 'Alt' key to expose the top menu bar.
2. Click 'Tools' and select 'Options.'

3. Click the 'Content' tab.
4. Check 'Enable JavaScript.'
5. Click 'Advanced,' located immediately to the right of 'Enable JavaScript.' Check 'Move or resize windows' to allow websites to change the size or position of your browsing window. Check 'Raise or lower windows' to allow sites to spawn windows above or below existing windows. Check 'Disable or replace context menus' to allow websites to change the pop-up menu that appears when you right-click a page. Click 'OK.'
6. Click 'OK' in the 'Options' window to save your settings and close the window.
7. Look for pop-up warnings, buttons on the toolbars or entries in the 'Tools' menu that relate to scripts. If you see something related to disabling scripts, usually you'll see an option to permanently or temporarily enable scripts for that page. Select that option to enabled JavaScripts, if the Add-on is blocking them. Numerous script-blocking Add-ons exist, so the procedure will vary depending on the Add-on used. If you are uncertain, consult your Add-on's documentation for more explicit instructions.
8. Check your Anti-virus or Firewall programs for 'Script Blocking' or 'Script Shields.' Again, the procedure for enabling scripts with these programs vary widely, so consult your software's documentation.