Install Unfriend Checker Chrome Extension for Facebook Install Unfriend Checker Opera Extension for Facebook Install Unfriend Firefox Firefox Addon for Facebook
Fluff Busting ( FB ) Purity

Bad news:
On September Facebook as forced all users to use new layout.
Because of that some addons/extensions will not be compatible with new Facebook theme, including Unfriend Checker.

Good news:
F.B. Purity addon will give u possibility to switch back to Facebook classic layout and will have back access to Unfriend Checker functionality.
In few days a new version of Unfriend Checker, compatible with new Facebook layout will be released.