You wouldn't even need a browser extension in Chrome, as it supports "greasemonkey" style user scripts natively: any `.user.js` file you drag onto the "chrome:/

You wouldn't even need a browser extension in Chrome, as it supports "greasemonkey" style user scripts natively: any `.user.js` file you drag onto the "chrome://extensions" page is converted to an anonymous Chrome extension automagicly. YMMV with other browsers, if course.