Deleting friends one by one can be annoying and irritating.Yes now lets learn how to Delete  Multiple Friends on Facebook.Now Lets do it wit help of some Scripts

Software Requirements

FireFox 4 or later

Download

Grease Monkey Add On

Download

Start:

First Install FireFox

Then Download Grease Monkey Add On

Install add on and Restart Firefox

Then Grease Monkey Icon will be visible on firefox(If itz not active click icon)

 Go to the download page(Click Install Script) and install the script

Install Script

Now a new popup window will ask you to Install Script

Click Install

 Installation Ends Here!

 Begin Deletion Now!

Go to ur Facebook Profile -> Friends

Wait till script loads

Hover over one of  ur friends name(Where Unfrend Really Comes)

Then Refresh the page

Now you will see Check Boxes aginst friends as seen bellow

Select the friends u want to Unfriend

Click on the Arrow Button as bellow 

Select Highlight Only Button

Now it will begin Deletion

Note: Be sure u select correct friends