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HTML::Tagset

Tagset(3)             User Contributed Perl Documentation            Tagset(3)



NAME
       HTML::Tagset - data tables useful in parsing HTML

VERSION
       Version 3.10

SYNOPSIS
         use HTML::Tagset;
         # Then use any of the items in the HTML::Tagset package
         #  as need arises

DESCRIPTION
       This module contains several data tables useful in various kinds of
       HTML parsing operations.

       Note that all tag names used are lowercase.

       In the following documentation, a "hashset" is a hash being used as a
       set -- the hash conveys that its keys are there, and the actual values
       associated with the keys are not significant.  (But what values are
       there, are always true.)

VARIABLES
       Note that none of these variables are exported.

       hashset %HTML::Tagset::emptyElement

       This hashset has as values the tag-names (GIs) of elements that cannot
       have content.  (For example, "base", "br", "hr".)  So
       $HTML::Tagset::emptyElement{'hr'} exists and is true.
       $HTML::Tagset::emptyElement{'dl'} does not exist, and so is not true.

       hashset %HTML::Tagset::optionalEndTag

       This hashset lists tag-names for elements that can have content, but
       whose end-tags are generally, "safely", omissible.  Example:
       $HTML::Tagset::emptyElement{'li'} exists and is true.

       hash %HTML::Tagset::linkElements

       Values in this hash are tagnames for elements that might contain links,
       and the value for each is a reference to an array of the names of
       attributes whose values can be links.

       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.

       hashset %HTML::Tagset::isPhraseMarkup

       This hashset contains all phrasal-level elements.

       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.

       hashset %HTML::Tagset::isHeadElement

       This hashset contains all elements that elements that should be present
       only in the 'head' element of an HTML document.

       hashset %HTML::Tagset::isList

       This hashset contains all elements that can contain "li" elements.

       hashset %HTML::Tagset::isTableElement

       This hashset contains all elements that are to be found only in/under a
       "table" element.

       hashset %HTML::Tagset::isFormElement

       This hashset contains all elements that are to be found only in/under a
       "form" element.

       hashset %HTML::Tagset::isBodyMarkup

       This hashset contains all elements that are to be found only in/under
       the "body" element of an HTML document.

       hashset %HTML::Tagset::isHeadOrBodyElement

       This hashset includes all elements that I notice can fall either in the
       head or in the body.

       hashset %HTML::Tagset::isKnown

       This hashset lists all known HTML elements.

       hashset %HTML::Tagset::canTighten

       This hashset lists elements that might have ignorable whitespace as
       children or siblings.

       array @HTML::Tagset::p_closure_barriers

       This array has a meaning that I have only seen a need for in
       "HTML::TreeBuilder", but I include it here on the off chance that some-
       one might find it of use:

       When we see a "<p>" token, we go lookup up the lineage for a p element
       we might have to minimize.  At first sight, we might say that if
       there's a p anywhere in the lineage of this new p, it should be closed.
       But that's wrong.  Consider this document:

         <html>
           <head>
             <title>foo</title>
           </head>
           <body>
             <p>foo
               <table>
                 <tr>
                   <td>
                      foo
                      <p>bar
                   </td>
                 </tr>
               </table>
             </p>
           </body>
         </html>

       The second p is quite legally inside a much higher p.

       My formalization of the reason why this is legal, but this:

         <p>foo<p>bar</p></p>

       isn't, is that something about the table constitutes a "barrier" to the
       application of the rule about what p must minimize.

       So @HTML::Tagset::p_closure_barriers is the list of all such bar-
       rier-tags.

       hashset %isCDATA_Parent

       This hashset includes all elements whose content is CDATA.

CAVEATS
       You may find it useful to alter the behavior of modules (like
       "HTML::Element" or "HTML::TreeBuilder") that use "HTML::Tagset"'s data
       tables by altering the data tables themselves.  You are welcome to try,
       but be careful; and be aware that different modules may or may react
       differently to the data tables being changed.

       Note that it may be inappropriate to use these tables for producing
       HTML -- for example, %isHeadOrBodyElement lists the tagnames for all
       elements that can appear either in the head or in the body, such as
       "script".  That doesn't mean that I am saying your code that produces
       HTML should feel free to put script elements in either place!  If you
       are producing programs that spit out HTML, you should be intimately
       familiar with the DTDs for HTML or XHTML (available at
       "http://www.w3.org/"), and you should slavishly obey them, not the data
       tables in this document.

SEE ALSO
       HTML::Element, HTML::TreeBuilder, HTML::LinkExtor

COPYRIGHT & LICENSE
       Copyright 1995-2000 Gisle Aas.

       Copyright 2000-2005 Sean M. Burke.

       Copyright 2005 Andy Lester.

       This program is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.

ACKNOWLEDGEMENTS
       Most of the code/data in this module was adapted from code written by
       Gisle Aas for "HTML::Element", "HTML::TreeBuilder", and "HTML::LinkEx-
       tor".  Then it was maintained by Sean M. Burke.

AUTHOR
       Current maintainer: Andy Lester, "<andy at petdance.com>"

BUGS
       Please report any bugs or feature requests to "bug-html-tagset at
       rt.cpan.org", or through the web interface at
       <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=HTML-Tagset>.  I will
       be notified, and then you'll automatically be notified of progress on
       your bug as I make changes.



perl v5.8.6                       2005-11-08                         Tagset(3)