(PHP 5, PHP 7, PHP 8, PECL tidy >= 0.5.2)
tidy::isXhtml -- tidy_is_xhtml — Indicates if the document is a XHTML document
面向对象风格
过程化风格
Tells if the document is a XHTML document.
   This function returns true if the specified tidy
   tidy is a XHTML document, or false otherwise.
  
    This function is not yet implemented in the Tidylib itself, so it always
    return false.