(PHP 5, PECL tidy >= 0.5.2)
tidy::isXhtml -- tidy_is_xhtml — Indicates if the document is a XHTML document
Object oriented style
Procedural style
Tells if the document is a XHTML document.
   This function returns TRUE if the specified tidy
   object is a XHTML document, or FALSE otherwise.
  
    This function is not yet implemented in the Tidylib itself, so it always
    return FALSE.