Every time I use Facebook, I get an "unresponsive script" error. Why?
Whenever I'm on Facebook, I get an "unresponsive script" error. A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete.
If it does work in Safe-mode then disable all your extensions and then try to find which is causing it by enabling one at a time until the problem reappears.
You can use "Disable all add-ons" on the Troubleshoot Firefox issues using Safe Mode start window to disable all extensions.
You have to close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")