From GreaseSpot Wiki
Greasemonkey is a user script manager. It is an extension for the Firefox web browser.
The official Greasemonkey home page is: http://www.greasespot.net/
The original creator of Greasemonkey, Aaron Boodman, said this about its creation:
- Greasemonkey was heavily inspired by Adrian Holovaty's site-specific extension for All Music Guide and the conversation which ensued after he published it. There were tons of sites I wanted to create SSE's for, but fully-fledged Firefox extensions proved too cumbersome. I wanted it to be as easy to create an SSE as it is to write DHTML.