Is there a Java Script or "UserScript" that allows users to run any JS on any page?
I was wondering because i know enough javascript to understand some of it and manipulate it, but i've only written one js Script for a site and it wasn't even that great. I know i can run custom java script through the console but that's not what i'm looking for.

Suggestions/Links would be great, also UserScripts.org is down and the mirror doesn't have a search function >.>