X-Ray is a new firefox extension that allows you to view the underlying HTML code on the page. Its simpler than going to view source, but shows less information, presumably to prevent long tags breaking the layout etc. For example you see <a> in front of a link and not the link.
One installed the X-Ray command is available by right-clicking as well as in the Tools menu. When applied to a page it can help you see how the document was constructed without having to go back and forth between the sourcecode and the page in your browser. Is that list made of li dd or p elements? Is that an h3 tag or just some bolded text? X-Ray shows you what’s beneath the surface of the page.
All in all well worth a look, but it would be nice if it was hosted by Mozilla and not on a blog, it works for me but YMMV.
Grab X-Ray here.
