Always at your service
Firebug is always just a keystroke away, but it never gets in your way.
Firebug also gives you fine-grained control over which websites you want to enable it for.
Inspect and edit HTML
Firebug makes it simple to find HTML elements buried deep in the page.
Visualize CSS metrics
When your CSS boxes aren’t lining up correctly it can be difficult to understand why.
Monitor online grid activity
Your pages are taking a long time to load, but why?
Did you go crazy and write too much JavaScript?
Did you forget to compress your images?
Are your ad partner’s servers taking a siesta?
Firebug breaks it all down for you file-by-file.