Differences between nxml-mode and nxhtml-mode?

Question

I installed nxml-mode and then nxhtml-mode (and they look great, real-time validation right inside my favorite editor is just sweet).

I understand that an XHTML file is an XML file and so I can use "just" nxml-mode to edit the XHTML. But I'm a bit confused: what does nxhtml-mode offer that nxml-mode does not?

If you were to edit XHTML, would you simply use nxml-mode or would you take the time to also install nxhtml-mode?

EDIT I've of course read the first page of nxhtml, where I downloaded nxhtml.

It says this, for example:

Completion and syntax checking for XHTML

So what kind of completion, for example, does it do that nxml-mode wouldn't do?

An example of something that can be done with nxhtml and that cannot be done with nxml would be really great.

Answer 1

The nXhtml homepage discusses exactly this in the first section.

When I tried to use nXhtml, the reason was mumamo, which is only included in nXhtml. I needed a mult-mode solution for Rails development. It turned out that it made Emacs too laggy and didn't work perfectly all the time. I gave up after a few weeks. I never tried the completion stuff.