How To Add Extra Features in Youtube Using Youtube Script

Guys its a amazing and you must love this .Sometimes we miss some features in youtube like a download option but with the help of this script you can add a download button below youtube player and you can also avoid some unused feature of youtube like Auto play .Today i am telling you a awesome script or say a plugin which add some extra feature in youtube .
Youtube Center Script
In this script you don't have to click to change the video resolution to the highest quality available .It's super easy to download a video . Just click on "Download" , to download your desired resolution and format ( You can change that in the settings ) . If you want to see the available formats and resolutions , click on the arrow , just next to "Download" , to show the menu .
If you are watching/listening to a video and you would like it to repeat . There's a simple button , "Repeat" , which you click on and the video will repeat until you click on the button again .
It's possible to use the YouTube player shortcuts like SPACE ( Play/Pause ) , outside of the player .

Have a look of its Features :
Download VideoButton
Repeat Video Button
HTML5 Support
MP3 Online Converter ( Link to an online converter in the download list ) - You need to activate this in the settings first .
Automatic selection of video resolution
YouTube Player shortcuts on page ( Shortcuts works outside of player ) .
Prevent YouTube to auto-play or auto-buffer
How to Install this script :
First Download Youtube Center Script from UpperScript .org .
Mozilla FireFox :
In Mozilla Firefox this Youtube Center script run through Greasemonkey
Steps :

you need to install Greasemonkey . After installation ( which requires restarting your browser )
Now go to Script Page , clicking on install button , link triggers Greasemonkey to pop up the script installation panel .
Greasemonkey shows you a list of what sites the script will run on and ask if you want to install the script .
Now loading a web page results in additional code ( the userscript ) being run .
In Google Chrome it will directly install the script . Just Install , and open youtube .com and use its features.