But as I wrap up the new design for my site, I’ve been using the HTML/CSS inspector function more and more. I’m easily able to see all the nested elements, their precise layout (with margins and paddings), as well as the styles applied to them. It takes all the guesswork out of Web design (okay, not all. This being a Firefox plugin, it’ll only show you how a site looks in Firefox). No more futzing around with coloured backgrounds or borders to test layouts!
If I had to find one fault, it’s that the HTML inspector is too tolerant of invalid code. Now that I’m at the stage of validating the XHTML, I’m finding a number of errors—such as incorrectly nested div’s—that (IMO) should have been caught by Firebug. But, oh well. No one tool can do everything.