Quix is an extensible bookmarklet, that allows you to easily access all your bookmarks and bookmarklets, across all your browsers, while maintaining them in only one spot. All you have to do is remember the shortcut for the bookmarklet, so, basically, it’s like a command line for your browser!
Quix comes with an enormous amount of powerful commands built in: check out the video below, or the first steps guide, after that, check out how to integrate it with your browser, and all the commands that are available by default.

An introduction to Quix from Joost de Valk on Vimeo.