Greasemonkey

Greasemonkey is a FireFox add-on which allows you to customize the look and feel of a particular website. It also allows certain functions like: Downloading youtube videos, blocking ads,etc

Go to the download link below to download and install Greasemonkey into Firefox. After restarting the browser you will see an icon of a monkey at the bottom-right. If it is in color it means that Greasemonkey is enabled. If it is faded it means that it is disabled.

To enable it go to Tools=> Greasemonkey => Enabled. Thats all.



 
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