The Web Developer extension adds a menu and a toolbar to the browser with various web developer tools. It is designed for Firefox, Flock, Mozilla and Seamonkey, and will run on any platform that these browsers support including Windows, Mac OS X and Linux. More than 20 languages supported. This is the handiest utility I've used. Mike
Yup. Firebug is more recent, and is a great compliment for the Web Developer Toolbar. But hey, I use Opera .