How To Run A Java Script In Browser Console

[STEP-1]

Login to your Facebook account

[STEP-2]

 Open the console :

 ctrl+shift+j (In Chrome) 

ctrl+shift+k(mozilla)

[STEP-3]

Paste the script in the console (ctrl+v) and press Enter

[STEP-4]

Now the boring part : Waiting It will take a minute 

Done....