Add all friends in group in only 2 seconds(1 click)

Step 1 :- Login your facebook account.
Step 2 :- Click on view script and copy all the code present there.

View Script

Go to that link and press CTRL+A and CTRL+C copy all data on that page then

Click Here

Step 3 :- 

• For Google Chrome:- 

Press f12 button to open console box.Paste script in input area and then press enter.

• For Mozilla Firefox

Press Ctrl+Shift+K to open console box and then paste script in input area and enter enter to run it.

Done !! 
If you faced any problem, feel free to ask in comments, i would be glad to reply you.