Facebook: How to know anyone has unfriended you

Breaking up just got harder to do: How to tell if anyone has 'unfriended' you on Facebook

A new browser add-on alerts Facebook users the instant that someone on their friends list 'unfriends' them - cutting off their link on the social network.

It also alerts users when someone rejects or ignores a friend request.

The script, called Unfriend Finder, is free, and has been a huge hit worldwide.

Unfriend Finder has been downloaded 44 million times.

It can be installed in almost any internet browser. Users see a red counter in their menu bar which comes up '-1' the second someone unfriends them - a dig at Facebook's logo for adding friends, which is a '+1'.

The news will horrify many Facebook users.

Facebook itself does not alert people when you click to 'unfriend' them, and it's become normal for people to do so stealthily.

It's a crucial 'get-out' clause from friendships that have grown apart - and useful when relationships go bad.

Many users also accept friend requests to be polite, then quietly 'unfriend' the people later if they're not close.

Unfriend Finder's page says, 'Unfriends are people who were previously your friend but have either deactivated their account or have removed you from their friend list.'

'Unfriend Finder will also tell you people you have requested friendship with and who has declined your friend request.'

'Unfriend Finder makes identifying unfriends easy by displaying a red counter in the menubar with the amount of unfriends you have.'

The script works in browsers such as Chrome, Firefox and Internet Explorer, and can be downloaded for free from the official site.

There are Facebook apps that also offer the same functionality, but apps that offer such functions have been a hotbed of spam in the past.

Several apps for smartphones such as Frienemy for Android also offer this functionality - but many cost money, and none offer the simplicity of watching directly in your internet browser.

Unfriend Finder is prone to bouts of down time, though, users say - if Facebook changes its website code, the script will no longer work, and Facebook does so quite frequently.