If you do any web development you know how hard it can be to decipher what is going on in someone else’s page you’d like to – let’s call it “emulate”. You also know how painful it can be to decipher layout issues like “why do I keep getting a scroll bar when all of my content appears within the browser window?”.
These issues are even more painful when AJAX is involved – because view source becomes useless.
Firebug is the only tool you’ll need to help you navigate those issues. I’ve only been using it for 2 months – and while I’m not a “web developer” strictly speaking (and maybe that is the point) it has become invaluable to me.
More from Wired and Webmonkey below:
On the surface, the Firebug extension for the Firefox browser is a simple page inspector. But lift the the hood and you’ll find a powerful code debugger and a variety of site-testing tools. Best of all, Firebug is just as extensible as the browser it plugs in to. Web developers can start cleaning up their code by following Webmonkey’s introductory guide to all things Firebug.
[From Get Started With Firebug, Firefox’s ‘Killer App’ for Web Developers]