Greasemonkey

Greasemonkey is a Firefox extension that lets you add bits of DHTML (user scripts) to any Web page to change its behavior. In much the same way that user CSS lets you take control of a Web page's style, user scripts let you easily control any aspect of a Web page's design or interaction. For example you could make sure all URLs displayed in the browser are clickable links, improve the usability of a site you frequent, route around common and annoying Web site bugs, or use the Coral content network selectively.

What is new in this release:

Version 1.11 fixed errors logged to the console when opening the "Websites..." Monkey Menu item and GM_openInTab() behavior when moving tabs across windows.

Requirements:

Firefox 14.0 or later