Installing GreaseMonkey

For those that dont know about how to installing Greasemonkey for adding javascript in firefox. What kind use of Greasemonkey.
GreaseMonkey Featured

Playing addons in facebook
Cheat Mafiawars and other game
Download from youtube with javascript so you dont need downloader of else
And many other function to make your life easier and fun

Installing GreaseMonkey

First Go to
https://addons.mozilla.org/en-US/firefox/addon/748

Now Click Add [...]