Greasemonkey and Firefox

Greasemonkey is a Firefox extension that allows user-created Javascripts to tweak Firefox in various ways. Greasemonkey scripts are like Firefox extensions, but much simpler. 
 You can download Greasemonkey from its page on Firefox add-ons . 
 Once you have it installed, go to userscripts.org to find some scripts. There’s no telling what you might find. To install a script, click on a link to the script’s .js file, and Greasemonkey will detect it automatically and let you install it. 
 If you need additional help, visit the official Greasemonkey website .