NOTE: the script is not functional at the moment (due to facebook API changes). I will remove this note once I make a new working version. Update Sep 2014:  I’ve created a new version of the script which works on recent Facebook. Apparently facebook allows you to easily remove single friends nowadays; so the script is extra useful for deleting bulk friends or inactive friends. To use the new script you don’t even need GreaseMonkey or TamperMonkey. Just follow these …