This is a great and simple script that does what it says, but since the recent YouTube redesign it doesn't work anymore. I made a modified version that works with the new design, get it here http://userscripts.org/scripts/show/162313

include https please.

Hello ! thank you for that great script but would it be possible you make it work with Youtube HTML5 player ?

I saw that the function "loop" works with HTML5 in "Youtube center" script (http://userscripts.org/scripts/show/114002)

However this script is not as "light" as yours ! please update your script and it will be f***ing perfect !

Thank you again !

Does exactly what it says, without unnecessary bloat or ugliness. Looks like it's part of the YouTube interface. Thanks!

Doesn't loop for some reason. Does not work on anything lower than Firefox 4?

Simple, yet works wonderfully. As it should.

A very needed feature that youtube for some darn reason haven't integrated into their interface. I hope you will keep it up to date, should youtube ever change and break the script.
Tested with Firefox 4 and Greasemonkey 0.9.5.