XHTML been an XML-based version of HTML and has been the subject of several W3C efforts ranging from XHTML 1.0 to XHTML Modularization and XHTML 2. The 2 version of the XHTML language was to offer ...

It includes HTML and XHTML tags both past and present, and shows you when the tag was deprecated, if it ever was. It's worth a bookmark if you're doing any web development or design, or if you ...