Firebug integrates with Firefox to put a wealth of development
tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.
Just the way you like itFirebug is always just a keystroke away, but it never gets in your way. You can open Firebug in a separate window, or as a bar at the bottom of your browser. Firebug also gives you fine-grained control over which websites you want to enable it for.
Inspect and edit HTMLFirebug makes it simple to find HTML elements buried deep in the page. Once you've found what you're looking for, Firebug gives you a wealth of information, and lets you edit the HTML live.
Tweak CSS to perfectionFirebug's CSS tabs tell you everything you need to know about the styles in your web pages, and if you don't like what it's telling you, you can make changes and see them take effect instantly.
More information about firebug at
getfirebug.com or you can download
here.