Is it possible to use JSF+Facelets with HTML 4/5?

Question

Facelets relies on XML namespaces to work with XHTML. How are HTML 4, and as far as I know, HTML 5 do not support namespaces. Also HTML 5 has some new elements that are not

Answer 1

http://wiki.whatwg.org/wiki/HTML_vs._XHTML has some useful information on how namespaces can be used in HTML5 to assist migration from XHTML. Perhaps you can try applying the namespace as it suggests and see what occurs?