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Parser(3)        User Contributed Perl Documentation       Parser(3)

       HTML::Parser - HTML parser class

        use HTML::Parser ();

        # Create parser object
        $p = HTML::Parser->new( api_version => 3,
                                start_h => [\&start, "tagname, attr"],
                                end_h   => [\&end,   "tagname"],
                                marked_sections => 1,

        # Parse document text chunk by chunk
        $p->eof;                 # signal end of document

        # Parse directly from file
        # or
        open(my $fh, "<:utf8", "foo.html") ⎪⎪ die;

       Objects of the "HTML::Parser" class will recognize markup and
       separate it from plain text (alias data content) in HTML doc‐
       uments.  As different kinds of markup and text are recog‐
       nized, the corresponding event handlers are invoked.

       "HTML::Parser" is not a generic SGML parser.  We have tried
       to make it able to deal with the HTML that is actually "out
       there", and it normally parses as closely as possible to the
       way the popular web browsers do it instead of strictly fol‐
       lowing one of the many HTML specifications from W3C.  Where
       there is disagreement, there is often an option that you can
       enable to get the official behaviour.

       The document to be parsed may be supplied in arbitrary
       chunks.  This makes on-the-fly parsing as documents are
       received from the network possible.

       If event driven parsing does not feel right for your applica‐
       tion, you might want to use "HTML::PullParser".  This is an
       "HTML::Parser" subclass that allows a more conventional pro‐
       gram structure.

       The following method is used to construct a new
       "HTML::Parser" object:

       $p = HTML::Parser->new( %options_and_handlers )
           This class method creates a new "HTML::Parser" object and
           returns it.  Key/value argument pairs may be provided to
           assign event handlers or initialize parser options.  The
           handlers and parser options can also be set or modified
           later by the method calls described below.

           If a top level key is in the form "<event>_h" (e.g.,
           "text_h") then it assigns a handler to that event, other‐
           wise it initializes a parser option. The event handler
           specification value must be an array reference.  Multiple
           handlers may also be assigned with the 'handlers =>
           [%handlers]' option.  See examples below.

           If new() is called without any arguments, it will create
           a parser that uses callback methods compatible with ver‐
           sion 2 of "HTML::Parser".  See the section on "version 2
           compatibility" below for details.

           The special constructor option 'api_version => 2' can be
           used to initialize version 2 callbacks while still set‐
           ting other options and handlers.  The 'api_version => 3'
           option can be used if you don't want to set any options
           and don't want to fall back to v2 compatible mode.


            $p = HTML::Parser->new(api_version => 3,
                                   text_h => [ sub {...}, "dtext" ]);

           This creates a new parser object with a text event han‐
           dler subroutine that receives the original text with gen‐
           eral entities decoded.

            $p = HTML::Parser->new(api_version => 3,
                                   start_h => [ 'my_start', "self,tokens" ]);

           This creates a new parser object with a start event han‐
           dler method that receives the $p and the tokens array.

            $p = HTML::Parser->new(api_version => 3,
                                   handlers => { text => [\@array, "event,text"],
                                                 comment => [\@array, "event,text"],

           This creates a new parser object that stores the event
           type and the original text in @array for text and comment

       The following methods feed the HTML document to the
       "HTML::Parser" object:

       $p->parse( $string )
           Parse $string as the next chunk of the HTML document.
           The return value is normally a reference to the parser
           object (i.e. $p).  Handlers invoked should not attempt to
           modify the $string in-place until $p->parse returns.

           If an invoked event handler aborts parsing by calling
           $p->eof, then $p->parse() will return a FALSE value.

       $p->parse( $code_ref )
           If a code reference is passed as the argument to be
           parsed, then the chunks to be parsed are obtained by
           invoking this function repeatedly.  Parsing continues
           until the function returns an empty (or undefined)
           result.  When this happens $p->eof is automatically sig‐

           Parsing will also abort if one of the event handlers
           calls $p->eof.

           The effect of this is the same as:

            while (1) {
               my $chunk = &$code_ref();
               if (!defined($chunk) ⎪⎪ !length($chunk)) {
                   return $p;
               $p->parse($chunk) ⎪⎪ return undef;

           But it is more efficient as this loop runs internally in
           XS code.

       $p->parse_file( $file )
           Parse text directly from a file.  The $file argument can
           be a filename, an open file handle, or a reference to an
           open file handle.

           If $file contains a filename and the file can't be
           opened, then the method returns an undefined value and $!
           tells why it failed.  Otherwise the return value is a
           reference to the parser object.

           If a file handle is passed as the $file argument, then
           the file will normally be read until EOF, but not closed.

           If an invoked event handler aborts parsing by calling
           $p->eof, then $p->parse_file() may not have read the
           entire file.

           On systems with multi-byte line terminators, the values
           passed for the offset and length argspecs may be too low
           if parse_file() is called on a file handle that is not in
           binary mode.

           If a filename is passed in, then parse_file() will open
           the file in binary mode.

           Signals the end of the HTML document.  Calling the
           $p->eof method outside a handler callback will flush any
           remaining buffered text (which triggers the "text" event
           if there is any remaining text).

           Calling $p->eof inside a handler will terminate parsing
           at that point and cause $p->parse to return a FALSE
           value.  This also terminates parsing by $p->parse_file().

           After $p->eof has been called, the parse() and
           parse_file() methods can be invoked to feed new documents
           with the parser object.

           The return value from eof() is a reference to the parser

       Most parser options are controlled by boolean attributes.
       Each boolean attribute is enabled by calling the correspond‐
       ing method with a TRUE argument and disabled with a FALSE
       argument.  The attribute value is left unchanged if no argu‐
       ment is given.  The return value from each method is the old
       attribute value.

       Methods that can be used to get and/or set parser options

       $p->attr_encoded( $bool )
           By default, the "attr" and @attr argspecs will have gen‐
           eral entities for attribute values decoded.  Enabling
           this attribute leaves entities alone.

       $p->boolean_attribute_value( $val )
           This method sets the value reported for boolean
           attributes inside HTML start tags.  By default, the name
           of the attribute is also used as its value.  This affects
           the values reported for "tokens" and "attr" argspecs.

       $p->case_sensitive( $bool )
           By default, tagnames and attribute names are down-cased.
           Enabling this attribute leaves them as found in the HTML
           source document.

       $p->closing_plaintext( $bool )
           By default, "plaintext" element can never be closed.
           Everything up to the end of the document is parsed in
           CDATA mode.  This historical behaviour is what at least
           MSIE does.  Enabling this attribute makes closing
           "</plaintext>" tag effective and the parsing process will
           resume after seeing this tag.  This emulates gecko-based

       $p->empty_element_tags( $bool )
           By default, empty element tags are not recognized as such
           and the "/" before ">" is just treated like a normal name
           character (unless "strict_names" is enabled).  Enabling
           this attribute make "HTML::Parser" recognize these tags.

           Empty element tags look like start tags, but end with the
           character sequence "/>" instead of ">".  When recognized
           by "HTML::Parser" they cause an artificial end event in
           addition to the start event.  The "text" for the artifi‐
           cial end event will be empty and the "tokenpos" array
           will be undefined even though the the token array will
           have one element containing the tag name.

       $p->marked_sections( $bool )
           By default, section markings like <![CDATA[...]]> are
           treated like ordinary text.  When this attribute is
           enabled section markings are honoured.

           There are currently no events associated with the marked
           section markup, but the text can be returned as

       $p->strict_comment( $bool )
           By default, comments are terminated by the first occur‐
           rence of "-->".  This is the behaviour of most popular
           browsers (like Mozilla, Opera and MSIE), but it is not
           correct according to the official HTML standard.  Offi‐
           cially, you need an even number of "--" tokens before the
           closing ">" is recognized and there may not be anything
           but whitespace between an even and an odd "--".

           The official behaviour is enabled by enabling this

           Enabling of 'strict_comment' also disables recognizing
           these forms as comments:

             </ comment>
             <! comment>

       $p->strict_end( $bool )
           By default, attributes and other junk are allowed to be
           present on end tags in a manner that emulates MSIE's be‐

           The official behaviour is enabled with this attribute.
           If enabled, only whitespace is allowed between the tag‐
           name and the final ">".

       $p->strict_names( $bool )
           By default, almost anything is allowed in tag and
           attribute names.  This is the behaviour of most popular
           browsers and allows us to parse some broken tags with
           invalid attribute values like:

              <IMG SRC=newprevlstGr.gif ALT=[PREV LIST] BORDER=0>

           By default, "LIST]" is parsed as a boolean attribute, not
           as part of the ALT value as was clearly intended.  This
           is also what Mozilla sees.

           The official behaviour is enabled by enabling this
           attribute.  If enabled, it will cause the tag above to be
           reported as text since "LIST]" is not a legal attribute

       $p->unbroken_text( $bool )
           By default, blocks of text are given to the text handler
           as soon as possible (but the parser takes care always to
           break text at a boundary between whitespace and non-
           whitespace so single words and entities can always be
           decoded safely).  This might create breaks that make it
           hard to do transformations on the text. When this
           attribute is enabled, blocks of text are always reported
           in one piece.  This will delay the text event until the
           following (non-text) event has been recognized by the

           Note that the "offset" argspec will give you the offset
           of the first segment of text and "length" is the combined
           length of the segments.  Since there might be ignored
           tags in between, these numbers can't be used to directly
           index in the original document file.

       $p->utf8_mode( $bool )
           Enable this option when parsing raw undecoded UTF-8.
           This tells the parser that the entities expanded for
           strings reported by "attr", @attr and "dtext" should be
           expanded as decoded UTF-8 so they end up compatible with
           the surrounding text.

           If "utf8_mode" is enabled then it is an error to pass
           strings containing characters with code above 255 to the
           parse() method, and the parse() method will croak if you

           Example: The Unicode character "\x{2665}" is
           "\xE2\x99\xA5" when UTF-8 encoded.  The character can
           also be represented by the entity "♥" or
           "♥".  If we feed the parser:


           then "dtext" will be reported as "\xE2\x99\xA5\x{2665}"
           without "utf8_mode" enabled, but as
           "\xE2\x99\xA5\xE2\x99\xA5" when enabled.  The later
           string is what you want.

           This option is only available with perl-5.8 or better.

       $p->xml_mode( $bool )
           Enabling this attribute changes the parser to allow some
           XML constructs.  This enables the behaviour controlled by
           individually by the "case_sensitive", "empty_ele‐
           ment_tags", "strict_names" and "xml_pic" attributes and
           also suppresses special treatment of elements that are
           parsed as CDATA for HTML.

       $p->xml_pic( $bool )
           By default, processing instructions are terminated by
           ">". When this attribute is enabled, processing instruc‐
           tions are terminated by "?>" instead.

       As markup and text is recognized, handlers are invoked.  The
       following method is used to set up handlers for different

       $p->handler( event => \&subroutine, $argspec )
       $p->handler( event => $method_name, $argspec )
       $p->handler( event => \@accum, $argspec )
       $p->handler( event => "" );
       $p->handler( event => undef );
       $p->handler( event );
           This method assigns a subroutine, method, or array to
           handle an event.

           Event is one of "text", "start", "end", "declaration",
           "comment", "process", "start_document", "end_document" or

           The "\&subroutine" is a reference to a subroutine which
           is called to handle the event.

           The $method_name is the name of a method of $p which is
           called to handle the event.

           The @accum is an array that will hold the event informa‐
           tion as sub-arrays.

           If the second argument is "", the event is ignored.  If
           it is undef, the default handler is invoked for the

           The $argspec is a string that describes the information
           to be reported for the event.  Any requested information
           that does not apply to a specific event is passed as
           "undef".  If argspec is omitted, then it is left

           The return value from $p->handler is the old callback
           routine or a reference to the accumulator array.

           Any return values from handler callback routines/methods
           are always ignored.  A handler callback can request pars‐
           ing to be aborted by invoking the $p->eof method.  A han‐
           dler callback is not allowed to invoke the $p->parse() or
           $p->parse_file() method.  An exception will be raised if
           it tries.


               $p->handler(start =>  "start", 'self, attr, attrseq, text' );

           This causes the "start" method of object $p to be called
           for 'start' events.  The callback signature is
           $p->start(\%attr, \@attr_seq, $text).

               $p->handler(start =>  \&start, 'attr, attrseq, text' );

           This causes subroutine start() to be called for 'start'
           events.  The callback signature is start(\%attr,
           \@attr_seq, $text).

               $p->handler(start =>  \@accum, '"S", attr, attrseq, text' );

           This causes 'start' event information to be saved in
           @accum.  The array elements will be ['S', \%attr,
           \@attr_seq, $text].

              $p->handler(start => "");

           This causes 'start' events to be ignored.  It also sup‐
           presses invocations of any default handler for start
           events.  It is in most cases equivalent to $p->han‐
           dler(start => sub {}), but is more efficient.  It is dif‐
           ferent from the empty-sub-handler in that "skipped_text"
           is not reset by it.

              $p->handler(start => undef);

           This causes no handler to be associated with start
           events.  If there is a default handler it will be

       Filters based on tags can be set up to limit the number of
       events reported.  The main bottleneck during parsing is often
       the huge number of callbacks made from the parser.  Applying
       filters can improve performance significantly.

       The following methods control filters:

       $p->ignore_elements( @tags )
           Both the "start" event and the "end" event as well as any
           events that would be reported in between are suppressed.
           The ignored elements can contain nested occurrences of
           itself.  Example:

              $p->ignore_elements(qw(script style));

           The "script" and "style" tags will always nest properly
           since their content is parsed in CDATA mode.  For most
           other tags "ignore_elements" must be used with caution
           since HTML is often not well formed.

       $p->ignore_tags( @tags )
           Any "start" and "end" events involving any of the tags
           given are suppressed.  To reset the filter (i.e. don't
           suppress any "start" and "end" events), call
           "ignore_tags" without an argument.

       $p->report_tags( @tags )
           Any "start" and "end" events involving any of the tags
           not given are suppressed.  To reset the filter (i.e.
           report all "start" and "end" events), call "report_tags"
           without an argument.

       Internally, the system has two filter lists, one for
       "report_tags" and one for "ignore_tags", and both filters are
       applied.  This effectively gives "ignore_tags" precedence
       over "report_tags".


          $p->report_tags(qw(script style));

       results in only "script" events being reported.


       Argspec is a string containing a comma-separated list that
       describes the information reported by the event.  The follow‐
       ing argspec identifier names can be used:

           Attr causes a reference to a hash of attribute name/value
           pairs to be passed.

           Boolean attributes' values are either the value set by
           $p->boolean_attribute_value, or the attribute name if no
           value has been set by $p->boolean_attribute_value.

           This passes undef except for "start" events.

           Unless "xml_mode" or "case_sensitive" is enabled, the
           attribute names are forced to lower case.

           General entities are decoded in the attribute values and
           one layer of matching quotes enclosing the attribute val‐
           ues is removed.

           The Unicode character set is assumed for entity decoding.
           With Perl version 5.6 or earlier only the Latin-1 range
           is supported, and entities for characters outside the
           range 0..255 are left unchanged.

           Basically the same as "attr", but keys and values are
           passed as individual arguments and the original sequence
           of the attributes is kept.  The parameters passed will be
           the same as the @attr calculated here:

              @attr = map { $_ => $attr->{$_} } @$attrseq;

           assuming $attr and $attrseq here are the hash and array
           passed as the result of "attr" and "attrseq" argspecs.

           This passes no values for events besides "start".

           Attrseq causes a reference to an array of attribute names
           to be passed.  This can be useful if you want to walk the
           "attr" hash in the original sequence.

           This passes undef except for "start" events.

           Unless "xml_mode" or "case_sensitive" is enabled, the
           attribute names are forced to lower case.

           Column causes the column number of the start of the event
           to be passed.  The first column on a line is 0.

           Dtext causes the decoded text to be passed.  General
           entities are automatically decoded unless the event was
           inside a CDATA section or was between literal start and
           end tags ("script", "style", "xmp", and "plaintext").

           The Unicode character set is assumed for entity decoding.
           With Perl version 5.6 or earlier only the Latin-1 range
           is supported, and entities for characters outside the
           range 0..255 are left unchanged.

           This passes undef except for "text" events.

           Event causes the event name to be passed.

           The event name is one of "text", "start", "end", "decla‐
           ration", "comment", "process", "start_document" or

           Is_cdata causes a TRUE value to be passed if the event is
           inside a CDATA section or between literal start and end
           tags ("script", "style", "xmp", and "plaintext").

           if the flag is FALSE for a text event, then you should
           normally either use "dtext" or decode the entities your‐
           self before the text is processed further.

           Length causes the number of bytes of the source text of
           the event to be passed.

           Line causes the line number of the start of the event to
           be passed.  The first line in the document is 1.  Line
           counting doesn't start until at least one handler
           requests this value to be reported.

           Offset causes the byte position in the HTML document of
           the start of the event to be passed.  The first byte in
           the document has offset 0.

           Offset_end causes the byte position in the HTML document
           of the end of the event to be passed.  This is the same
           as "offset" + "length".

           Self causes the current object to be passed to the han‐
           dler.  If the handler is a method, this must be the first
           element in the argspec.

           An alternative to passing self as an argspec is to regis‐
           ter closures that capture $self by themselves as han‐
           dlers.  Unfortunately this creates circular references
           which prevent the HTML::Parser object from being garbage
           collected.  Using the "self" argspec avoids this problem.

           Skipped_text returns the concatenated text of all the
           events that have been skipped since the last time an
           event was reported.  Events might be skipped because no
           handler is registered for them or because some filter
           applies.  Skipped text also includes marked section
           markup, since there are no events that can catch it.

           If an ""-handler is registered for an event, then the
           text for this event is not included in "skipped_text".
           Skipped text both before and after the ""-event is
           included in the next reported "skipped_text".

           Same as "tagname", but prefixed with "/" if it belongs to
           an "end" event and "!" for a declaration.  The "tag" does
           not have any prefix for "start" events, and is in this
           case identical to "tagname".

           This is the element name (or generic identifier in SGML
           jargon) for start and end tags.  Since HTML is case
           insensitive, this name is forced to lower case to ease
           string matching.

           Since XML is case sensitive, the tagname case is not
           changed when "xml_mode" is enabled.  The same happens if
           the "case_sensitive" attribute is set.

           The declaration type of declaration elements is also
           passed as a tagname, even if that is a bit strange.  In
           fact, in the current implementation tagname is identical
           to "token0" except that the name may be forced to lower

           Token0 causes the original text of the first token string
           to be passed.  This should always be the same as

           For "declaration" events, this is the declaration type.

           For "start" and "end" events, this is the tag name.

           For "process" and non-strict "comment" events, this is
           everything inside the tag.

           This passes undef if there are no tokens in the event.

           Tokenpos causes a reference to an array of token posi‐
           tions to be passed.  For each string that appears in
           "tokens", this array contains two numbers.  The first
           number is the offset of the start of the token in the
           original "text" and the second number is the length of
           the token.

           Boolean attributes in a "start" event will have (0,0) for
           the attribute value offset and length.

           This passes undef if there are no tokens in the event
           (e.g., "text") and for artificial "end" events triggered
           by empty element tags.

           If you are using these offsets and lengths to modify
           "text", you should either work from right to left, or be
           very careful to calculate the changes to the offsets.

           Tokens causes a reference to an array of token strings to
           be passed.  The strings are exactly as they were found in
           the original text, no decoding or case changes are

           For "declaration" events, the array contains each word,
           comment, and delimited string starting with the declara‐
           tion type.

           For "comment" events, this contains each sub-comment.  If
           $p->strict_comments is disabled, there will be only one

           For "start" events, this contains the original tag name
           followed by the attribute name/value pairs.  The values
           of boolean attributes will be either the value set by
           $p->boolean_attribute_value, or the attribute name if no
           value has been set by $p->boolean_attribute_value.

           For "end" events, this contains the original tag name
           (always one token).

           For "process" events, this contains the process instruc‐
           tions (always one token).

           This passes "undef" for "text" events.

           Text causes the source text (including markup element
           delimiters) to be passed.

           Pass an undefined value.  Useful as padding where the
           same handler routine is registered for multiple events.

           A literal string of 0 to 255 characters enclosed in sin‐
           gle (') or double (") quotes is passed as entered.

       The whole argspec string can be wrapped up in '@{...}' to
       signal that the resulting event array should be flattened.
       This only makes a difference if an array reference is used as
       the handler target.  Consider this example:

          $p->handler(text => [], 'text');
          $p->handler(text => [], '@{text}']);

       With two text events; "foo", "bar"; then the first example
       will end up with [["foo"], ["bar"]] and the second with
       ["foo", "bar"] in the handler target array.


       Handlers for the following events can be registered:

           This event is triggered when a markup comment is recog‐


             <!-- This is a comment -- -- So is this -->

           This event is triggered when a markup declaration is rec‐

           For typical HTML documents, the only declaration you are
           likely to find is <!DOCTYPE ...>.


             <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"

           DTDs inside <!DOCTYPE ...> will confuse HTML::Parser.

           This event is triggered for events that do not have a
           specific handler.  You can set up a handler for this
           event to catch stuff you did not want to catch explic‐

           This event is triggered when an end tag is recognized.



           This event is triggered when $p->eof is called and after
           any remaining text is flushed.  There is no document text
           associated with this event.

           This event is triggered when a processing instructions
           markup is recognized.

           The format and content of processing instructions are
           system and application dependent.


             <? HTML processing instructions >
             <? XML processing instructions ?>

           This event is triggered when a start tag is recognized.


             <A HREF="">

           This event is triggered before any other events for a new
           document.  A handler for it can be used to initialize
           stuff.  There is no document text associated with this

           This event is triggered when plain text (characters) is
           recognized.  The text may contain multiple lines.  A
           sequence of text may be broken between several text
           events unless $p->unbroken_text is enabled.

           The parser will make sure that it does not break a word
           or a sequence of whitespace between two text events.


       The "HTML::Parser" can parse Unicode strings when running
       under perl-5.8 or better.  If Unicode is passed to
       $p->parse() then chunks of Unicode will be reported to the
       handlers.  The offset and length argspecs will also report
       their position in terms of characters.

       It is safe to parse raw undecoded UTF-8 if you either avoid
       decoding entities and make sure to not use argspecs that do,
       or enable the "utf8_mode" for the parser.  Parsing of unde‐
       coded UTF-8 might be useful when parsing from a file where
       you need the reported offsets and lengths to match the byte
       offsets in the file.

       If a filename is passed to $p->parse_file() then the file
       will be read in binary mode.  This will be fine if the file
       contains only ASCII or Latin-1 characters.  If the file con‐
       tains UTF-8 encoded text then care must be taken when decod‐
       ing entities as described in the previous paragraph, but bet‐
       ter is to open the file with the UTF-8 layer so that it is
       decoded properly:

          open(my $fh, "<:utf8", "index.html") ⎪⎪ die "...: $!";

       If the file contains text encoded in a charset besides ASCII,
       Latin-1 or UTF-8 then decoding will always be needed.

       When an "HTML::Parser" object is constructed with no argu‐
       ments, a set of handlers is automatically provided that is
       compatible with the old HTML::Parser version 2 callback meth‐

       This is equivalent to the following method calls:

          $p->handler(start   => "start",   "self, tagname, attr, attrseq, text");
          $p->handler(end     => "end",     "self, tagname, text");
          $p->handler(text    => "text",    "self, text, is_cdata");
          $p->handler(process => "process", "self, token0, text");
          $p->handler(comment =>
                    sub {
                        my($self, $tokens) = @_;
                        for (@$tokens) {$self->comment($_);}},
                    "self, tokens");
          $p->handler(declaration =>
                    sub {
                        my $self = shift;
                        $self->declaration(substr($_[0], 2, -1));},
                    "self, text");

       Setting up these handlers can also be requested with the
       "api_version => 2" constructor option.

       The "HTML::Parser" class is subclassable.  Parser objects are
       plain hashes and "HTML::Parser" reserves only hash keys that
       start with "_hparser".  The parser state can be set up by
       invoking the init() method, which takes the same arguments as

       The first simple example shows how you might strip out com‐
       ments from an HTML document.  We achieve this by setting up a
       comment handler that does nothing and a default handler that
       will print out anything else:

         use HTML::Parser;
         HTML::Parser->new(default_h => [sub { print shift }, 'text'],
                           comment_h => [""],
                          )->parse_file(shift ⎪⎪ die) ⎪⎪ die $!;

       An alternative implementation is:

         use HTML::Parser;
         HTML::Parser->new(end_document_h => [sub { print shift },
                           comment_h      => [""],
                          )->parse_file(shift ⎪⎪ die) ⎪⎪ die $!;

       This will in most cases be much more efficient since only a
       single callback will be made.

       The next example prints out the text that is inside the
       <title> element of an HTML document.  Here we start by set‐
       ting up a start handler.  When it sees the title start tag it
       enables a text handler that prints any text found and an end
       handler that will terminate parsing as soon as the title end
       tag is seen:

         use HTML::Parser ();

         sub start_handler
           return if shift ne "title";
           my $self = shift;
           $self->handler(text => sub { print shift }, "dtext");
           $self->handler(end  => sub { shift->eof if shift eq "title"; },

         my $p = HTML::Parser->new(api_version => 3);
         $p->handler( start => \&start_handler, "tagname,self");
         $p->parse_file(shift ⎪⎪ die) ⎪⎪ die $!;
         print "\n";

       More examples are found in the eg/ directory of the
       "HTML-Parser" distribution: the program "hrefsub" shows how
       you can edit all links found in a document; the program
       "htextsub" shows how to edit the text only; the program
       "hstrip" shows how you can strip out certain tags/elements
       and/or attributes; and the program "htext" show how to obtain
       the plain text, but not any script/style content.

       You can browse the eg/ directory online from the [Browse]
       link on the page.

       The <style> and <script> sections do not end with the first
       "</", but need the complete corresponding end tag.  The stan‐
       dard behaviour is not really practical.

       When the strict_comment option is enabled, we still recognize
       comments where there is something other than whitespace
       between even and odd "--" markers.

       Once $p->boolean_attribute_value has been set, there is no
       way to restore the default behaviour.

       There is currently no way to get both quote characters into
       the same literal argspec.

       Empty tags, e.g. "<>" and "</>", are not recognized.  SGML
       allows them to repeat the previous start tag or close the
       previous start tag respectively.

       NET tags, e.g. "code/.../" are not recognized.  This is SGML
       shorthand for "<code>...</code>".

       Unclosed start or end tags, e.g. "<tt<b>...</b</tt>" are not

       The following messages may be produced by HTML::Parser.  The
       notation in this listing is the same as used in perldiag:

       Not a reference to a hash
           (F) The object blessed into or subclassed from
           HTML::Parser is not a hash as required by the
           HTML::Parser methods.

       Bad signature in parser state object at %p
           (F) The _hparser_xs_state element does not refer to a
           valid state structure.  Something must have changed the
           internal value stored in this hash element, or the memory
           has been overwritten.

       _hparser_xs_state element is not a reference
           (F) The _hparser_xs_state element has been destroyed.

       Can't find '_hparser_xs_state' element in HTML::Parser hash
           (F) The _hparser_xs_state element is missing from the
           parser hash.  It was either deleted, or not created when
           the object was created.

       API version %s not supported by HTML::Parser %s
           (F) The constructor option 'api_version' with an argument
           greater than or equal to 4 is reserved for future exten‐

       Bad constructor option '%s'
           (F) An unknown constructor option key was passed to the
           new() or init() methods.

       Parse loop not allowed
           (F) A handler invoked the parse() or parse_file() method.
           This is not permitted.

       marked sections not supported
           (F) The $p->marked_sections() method was invoked in a
           HTML::Parser module that was compiled without support for
           marked sections.

       Unknown boolean attribute (%d)
           (F) Something is wrong with the internal logic that set
           up aliases for boolean attributes.

       Only code or array references allowed as handler
           (F) The second argument for $p->handler must be either a
           subroutine reference, then name of a subroutine or
           method, or a reference to an array.

       No handler for %s events
           (F) The first argument to $p->handler must be a valid
           event name; i.e. one of "start", "end", "text",
           "process", "declaration" or "comment".

       Unrecognized identifier %s in argspec
           (F) The identifier is not a known argspec name.  Use one
           of the names mentioned in the argspec section above.

       Literal string is longer than 255 chars in argspec
           (F) The current implementation limits the length of lit‐
           erals in an argspec to 255 characters.  Make the literal

       Backslash reserved for literal string in argspec
           (F) The backslash character "\" is not allowed in argspec
           literals.  It is reserved to permit quoting inside a lit‐
           eral in a later version.

       Unterminated literal string in argspec
           (F) The terminating quote character for a literal was not

       Bad argspec (%s)
           (F) Only identifier names, literals, spaces and commas
           are allowed in argspecs.

       Missing comma separator in argspec
           (F) Identifiers in an argspec must be separated with ",".

       Parsing of undecoded UTF-8 will give garbage when decoding
           (W) The first chunk parsed appears to contain undecoded
           UTF-8 and one or more argspecs that decode entities are
           used for the callback handlers.

           The result of decoding will be a mix of encoded and
           decoded characters for any entities that expand to char‐
           acters with code above 127.  This is not a good thing.

           The solution is to use the Encode::encode_utf8() on the
           data before feeding it to the $p->parse().  For
           $p->parse_file() pass a file that has been opened in
           ":utf8" mode.

           The parser can process raw undecoded UTF-8 sanely if the
           "utf8_mode" is enabled or if the "attr", "@attr" or
           "dtext" argspecs is avoided.

       Parsing string decoded with wrong endianess
           (W) The first character in the document is U+FFFE.  This
           is not a legal Unicode character but a byte swapped BOM.
           The result of parsing will likely be garbage.

       Parsing of undecoded UTF-32
           (W) The parser found the Unicode UTF-32 BOM signature at
           the start of the document.  The result of parsing will
           likely be garbage.

       Parsing of undecoded UTF-16
           (W) The parser found the Unicode UTF-16 BOM signature at
           the start of the document.  The result of parsing will
           likely be garbage.

       HTML::Entities, HTML::PullParser, HTML::TokeParser,
       HTML::HeadParser, HTML::LinkExtor, HTML::Form

       HTML::TreeBuilder (part of the HTML-Tree distribution)

       More information about marked sections and processing
       instructions may be found at

        Copyright 1996-2007 Gisle Aas. All rights reserved.
        Copyright 1999-2000 Michael A. Chase.  All rights reserved.

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

perl v5.8.8                  2006-04-26                    Parser(3)
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