How can I validate XMTML1 strict from W3C in spite of iframe

            <p>
               <?php
                  include_once("fckeditor/fckeditor.php") ;
                  $oFCKeditor = new FCKeditor('FCKeditor1') ;
                  $oFCKeditor->BasePath = 'fckeditor/' ;
                  $oFCKeditor->Value = '' ;
                  $oFCKeditor->Create() ;
               ?>
            </p>

Use a textarea and replace it with javascript. That way you will pass validation and with the benefit that if the user has disabled javascript he still will be able to fill the form.