anchor.diff:  allow_elt(<<"th">>) -> true;
   allow_elt(<<"tr">>) -> true;
   allow_elt(<<"ul">>) -> true;
  +allow_elt(<<"video">>) -> true;
   allow_elt(_) -> false.
   
   %% @doc Allowed attributes
   allow_attr(<<"align">>) -> true;
   allow_attr(<<"alt">>) -> true;
  +allow_attr(<<"autoplay">>) -> true;
   allow_attr(<<"border">>) -> true;
   allow_attr(<<"borderspacing">>) -> true;
   allow_attr(<<"cellpadding">>) -> true;
   allow_attr(<<"cellspacing">>) -> true;
   allow_attr(<<"class">>) -> true;
   allow_attr(<<"colspan">>) -> true;
  +allow_attr(<<"controls">>) -> true;
   allow_attr(<<"coords">>) -> true;
   allow_attr(<<"dir">>) -> true;
   allow_attr(<<"height">>) -> true;
   allow_attr(<<"href">>) -> true;
   %allow_attr(<<"id">>) -> true;
  +allow_attr(<<"loop">>) -> true;
   allow_attr(<<"name">>) -> true;
  +allow_attr(<<"poster">>) -> true;
  +allow_attr(<<"preload">>) -> true;
   allow_attr(<<"rowspan">>) -> true;
   allow_attr(<<"shape">>) -> true;
   allow_attr(<<"src">>) -> true;
  
positive.code: allow_once(_) -> false.
  
  %% @doc Allowed elements (see also allow_once/1 above)
  allow_elt(<<"blockquote">>) -> true;
  allow_elt(<<"caption">>) -> true;
  allow_elt(<<"col">>) -> true;
  
negative.code: %% @doc Check if the attribute might contain an url
  is_url_attr(<<"src">>) -> true;
  is_url_attr(<<"href">>) -> true;
  is_url_attr(<<"poster">>) -> true;
  is_url_attr(_) -> false.
  
  %% @doc Elements that shouldn't use a open and close tag.
  