'body'    => ['background'],
 'del'     => ['cite'],
 'embed'   => ['pluginspage', 'src'],
 'form'    => ['action'],
 'frame'   => ['src', 'longdesc'],
 'iframe'  => ['src', 'longdesc'],
 'ilayer'  => ['background'],
 'img'     => ['src', 'lowsrc', 'longdesc', 'usemap'],
 'input'   => ['src', 'usemap'],
 'ins'     => ['cite'],
 'isindex' => ['action'],
 'head'    => ['profile'],
 'layer'   => ['background', 'src'],
 'link'    => ['href'],
 'object'  => ['classid', 'codebase', 'data', 'archive', 'usemap'],
 'q'       => ['cite'],
 'script'  => ['src', 'for'],
 'table'   => ['background'],
 'td'      => ['background'],
 'th'      => ['background'],
 'tr'      => ['background'],
 'xmp'     => ['href'],
);

=head2 hash %HTML::Tagset::boolean_attr

This hash (not hashset) lists what attributes of what elements can be
printed without showing the value (for example, the "noshade" attribute
of "hr" elements).  For elements with only one such attribute, its value
is simply that attribute name.  For elements with many such attributes,
the value is a reference to a hashset containing all such attributes.

=cut

%boolean_attr = (
# TODO: make these all hashes
  'area'   => 'nohref',
  'dir'    => 'compact',
  'dl'     => 'compact',
  'hr'     => 'noshade',
  'img'    => 'ismap',
  'input'  => { 'checked' => 1, 'readonly' => 1, 'disabled' => 1 },
  'menu'   => 'compact',
  'ol'     => 'compact',
  'option' => 'selected',
  'select' => 'multiple',
  'td'     => 'nowrap',
  'th'     => 'nowrap',
  'ul'     => 'compact',
);

#==========================================================================
# List of all elements from Extensible HTML version 1.0 Transitional DTD:
#
#   a abbr acronym address applet area b base basefont bdo big
#   blockquote body br button caption center cite code col colgroup
#   dd del dfn dir div dl dt em fieldset font form h1 h2 h3 h4 h5 h6
#   head hr html i iframe img input ins isindex kbd label legend li
#   link map menu meta noframes noscript object ol optgroup option p
#   param pre q s samp script select small span strike strong style
#   sub sup table tbody td textarea tfoot th thead title tr tt u ul
#   var
#
# Varia from Mozilla source internal table of tags:
#   Implemented:
#     xmp listing wbr nobr frame frameset noframes ilayer
#     layer nolayer spacer embed multicol
#   But these are unimplemented:
#     sound??  keygen??  server??
# Also seen here and there:
#     marquee??  app??  (both unimplemented)
#==========================================================================

=head2 hashset %HTML::Tagset::isPhraseMarkup

This hashset contains all phrasal-level elements.

=cut

%isPhraseMarkup = map {; $_ => 1 } qw(
  span abbr acronym q sub sup
  cite code em kbd samp strong var dfn strike
  b i u s tt small big 
  a img br
  wbr nobr blink
  font basefont bdo
  spacer embed noembed
);  # had: center, hr, table


=head2 hashset %HTML::Tagset::is_Possible_Strict_P_Content

This hashset contains all phrasal-level elements that be content of a
P element, for a strict model of HTML.

=cut

%is_Possible_Strict_P_Content = (
 %isPhraseMarkup,
 %isFormElement,