Dirhtml Help - XHTML

Dirhtml can generate web pages compliant with strict or transitional XHTML 1.0 .  XHTML is very similar to HTML 4.01, with a few exceptions.

Naturally, if a script isn't XHTML compliant, files generated using it will not be XHTML compliant either.

For more information on xhtml, try a Google/Bing search or this page.

Some of the differences between XHTML 1.0 and HTML 4.0 include:

The target doctype can be changed on the Miscellaneous page or by redefining /DOCTYPE in a script.

Dirhtml nominally supports HTML-5.  Dirhtml-generated HTML-5 files really just XHTML Strict files with a different html doctype.