Userscripts.org (->browser) different of jsdo.it : power-ups for your browser ; user.js->extension

Userscripts.org: Power-ups for your browser:

http://userscripts.org/

compare userscript.org and jsdo.it

http://userscripts.org/about/installing
Chrome has an "auto-Greasemonkey". Greasemonkey is an extension for Mozilla Firefox, an open source Web Browser. Most userscripts are written for Firefox & Greasemonkey (although some work in Opera, Safari,Chrome and even Internet Explorer).

-----------------------