<?php
class HTML5 {
    private $data;
    private $char;
    private $EOF;
    private $state;
    private $tree;
    private $token;
    private $content_model;
    private $escape = false;
    private $entities = array('AElig;','AElig','AMP;','AMP','Aacute;','Aacute',
    'Acirc;','Acirc','Agrave;','Agrave','Alpha;','Aring;','Aring','Atilde;',
    'Atilde','Auml;','Auml','Beta;','COPY;','COPY','Ccedil;','Ccedil','Chi;',
    'Dagger;','Delta;','ETH;','ETH','Eacute;','Eacute','Ecirc;','Ecirc','Egrave;',
    'Egrave','Epsilon;','Eta;','Euml;','Euml','GT;','GT','Gamma;','Iacute;',
    'Iacute','Icirc;','Icirc','Igrave;','Igrave','Iota;','Iuml;','Iuml','Kappa;',
    'LT;','LT','Lambda;','Mu;','Ntilde;','Ntilde','Nu;','OElig;','Oacute;',
    'Oacute','Ocirc;','Ocirc','Ograve;','Ograve','Omega;','Omicron;','Oslash;',
    'Oslash','Otilde;','Otilde','Ouml;','Ouml','Phi;','Pi;','Prime;','Psi;',
    'QUOT;','QUOT','REG;','REG','Rho;','Scaron;','Sigma;','THORN;','THORN',
    'TRADE;','Tau;','Theta;','Uacute;','Uacute','Ucirc;','Ucirc','Ugrave;',
    'Ugrave','Upsilon;','Uuml;','Uuml','Xi;','Yacute;','Yacute','Yuml;','Zeta;',
    'aacute;','aacute','acirc;','acirc','acute;','acute','aelig;','aelig',
    'agrave;','agrave','alefsym;','alpha;','amp;','amp','and;','ang;','apos;',
    'aring;','aring','asymp;','atilde;','atilde','auml;','auml','bdquo;','beta;',
    'brvbar;','brvbar','bull;','cap;','ccedil;','ccedil','cedil;','cedil',
    'cent;','cent','chi;','circ;','clubs;','cong;','copy;','copy','crarr;',
    'cup;','curren;','curren','dArr;','dagger;','darr;','deg;','deg','delta;',
    'diams;','divide;','divide','eacute;','eacute','ecirc;','ecirc','egrave;',
    'egrave','empty;','emsp;','ensp;','epsilon;','equiv;','eta;','eth;','eth',
    'euml;','euml','euro;','exist;','fnof;','forall;','frac12;','frac12',
    'frac14;','frac14','frac34;','frac34','frasl;','gamma;','ge;','gt;','gt',
    'hArr;','harr;','hearts;','hellip;','iacute;','iacute','icirc;','icirc',
    'iexcl;','iexcl','igrave;','igrave','image;','infin;','int;','iota;',
    'iquest;','iquest','isin;','iuml;','iuml','kappa;','lArr;','lambda;','lang;',
    'laquo;','laquo','larr;','lceil;','ldquo;','le;','lfloor;','lowast;','loz;',
    'lrm;','lsaquo;','lsquo;','lt;','lt','macr;','macr','mdash;','micro;','micro',
    'middot;','middot','minus;','mu;','nabla;','nbsp;','nbsp','ndash;','ne;',
    'ni;','not;','not','notin;','nsub;','ntilde;','ntilde','nu;','oacute;',
    'oacute','ocirc;','ocirc','oelig;','ograve;','ograve','oline;','omega;',
    'omicron;','oplus;','or;','ordf;','ordf','ordm;','ordm','oslash;','oslash',
    'otilde;','otilde','otimes;','ouml;','ouml','para;','para','part;','permil;',
    'perp;','phi;','pi;','piv;','plusmn;','plusmn','pound;','pound','prime;',
    'prod;','prop;','psi;','quot;','quot','rArr;','radic;','rang;','raquo;',
    'raquo','rarr;','rceil;','rdquo;','real;','reg;','reg','rfloor;','rho;',
    'rlm;','rsaquo;','rsquo;','sbquo;','scaron;','sdot;','sect;','sect','shy;',
    'shy','sigma;','sigmaf;','sim;','spades;','sub;','sube;','sum;','sup1;',
    'sup1','sup2;','sup2','sup3;','sup3','sup;','supe;','szlig;','szlig','tau;',
    'there4;','theta;','thetasym;','thinsp;','thorn;','thorn','tilde;','times;',
    'times','trade;','uArr;','uacute;','uacute','uarr;','ucirc;','ucirc',
    'ugrave;','ugrave','uml;','uml','upsih;','upsilon;','uuml;','uuml','weierp;',
    'xi;','yacute;','yacute','yen;','yen','yuml;','yuml','zeta;','zwj;','zwnj;');

    const PCDATA    = 0;
    const RCDATA    = 1;
    const CDATA     = 2;
    const PLAINTEXT = 3;

    const DOCTYPE  = 0;
    const STARTTAG = 1;
    const ENDTAG   = 2;
    const COMMENT  = 3;
    const CHARACTR = 4;
    const EOF      = 5;

    public function __construct($data) {
        $data = str_replace("\r\n", "\n", $data);
        $date = str_replace("\r", null, $data);

        $this->data = $data;
        $this->char = -1;
        $this->EOF  = strlen($data);
        $this->tree = new HTML5TreeConstructer;
        $this->content_model = self::PCDATA;

        $this->state = 'data';

        while($this->state !== null) {
            $this->{$this->state.'State'}();
        }
    }

    public function save() {
        return $this->tree->save();
    }

    private function char() {
        return ($this->char < $this->EOF)
            ? $this->data[$this->char]
            : false;
    }

    private function character($s, $l = 0) {
        if($s + $l < $this->EOF) {
            if($l === 0) {
                return $this->data[$s];
            } else {
                return substr($this->data, $s, $l);
            }
        }
    }

    private function characters($char_class, $start) {
        return preg_replace('#^(['.$char_class.']+).*#s', '\\1', substr($this->data, $start));
    }

    private function dataState() {
        // Consume the next input character
        $this->char++;
        $char = $this->char();

        if($char === '&' && ($this->content_model === self::PCDATA || $this->content_model === self::RCDATA)) {
            /* U+0026 AMPERSAND (&)
            When the content model flag is set to one of the PCDATA or RCDATA
            states: switch to the entity data state. Otherwise: treat it as per
            the "anything else"    entry below. */
            $this->state = 'entityData';

        } elseif($char === '-') {
            /* If the content model flag is set to either the RCDATA state or
            the CDATA state, and the escape flag is false, and there are at
            least three characters before this one in the input stream, and the
            last four characters in the input stream, including this one, are
            U+003C LESS-THAN SIGN, U+0021 EXCLAMATION MARK, U+002D HYPHEN-MINUS,
            and U+002D HYPHEN-MINUS ("<!--"), then set the escape flag to true. */
            if(($this->content_model === self::RCDATA || $this->content_model ===
            self::CDATA) && $this->escape === false &&
            $this->char >= 3 && $this->character($this->char - 4, 4) === '<!--') {
                $this->escape = true;
            }

            /* In any case, emit the input character as a character token. Stay
            in the data state. */
            $this->emitToken(array(
                'type' => self::CHARACTR,
                'data' => $char
            ));

        /* U+003C LESS-THAN SIGN (<) */
        } elseif($char === '<' && ($this->content_model === self::PCDATA ||
        (($this->content_model === self::RCDATA ||
        $this->content_model === self::CDATA) && $this->escape === false))) {
            /* When the content model flag is set to the PCDATA state: switch
            to the tag open state.

            When the content model flag is set to either the RCDATA state or
            the CDATA state and the escape flag is false: switch to the tag
            open state.

            Otherwise: treat it as per the "anything else" entry below. */
            $this->state = 'tagOpen';

        /* U+003E GREATER-THAN SIGN (>) */
        } elseif($char === '>') {
            /* If the content model flag is set to either the RCDATA state or
            the CDATA state, and the escape flag is true, and the last three
            characters in the input stream including this one are U+002D
            HYPHEN-MINUS, U+002D HYPHEN-MINUS, U+003E GREATER-THAN SIGN ("-->"),
            set the escape flag to false. */
            if(($this->content_model === self::RCDATA ||
            $this->content_model === self::CDATA) && $this->escape === true &&
            $this->character($this->char, 3) === '-->') {
                $this->escape = false;
            }

            /* In any case, emit the input character as a character token.
            Stay in the data state. */
            $this->emitToken(array(
                'type' => self::CHARACTR,
                'data' => $char
            ));

        } elseif($this->char === $this->EOF) {
            /* EOF
            Emit an end-of-file token. */
            $this->EOF();

        } elseif($this->content_model === self::PLAINTEXT) {
            /* When the content model flag is set to the PLAINTEXT state
            THIS DIFFERS GREATLY FROM THE SPEC: Get the remaining characters of
            the text and emit it as a character token. */
            $this->emitToken(array(
                'type' => self::CHARACTR,
                'data' => substr($this->data, $this->char)
            ));

            $this->EOF();

        } else {
            /* Anything else
            THIS DIFFERS GREATLY FROM THE SPEC: Get as many character that
            otherwise would also be treated as a character token and emit it
            as a single character token. Stay in the data state. */
            $len  = strcspn($this->data, '<&', $this->char);
            $char = substr($this->data, $this->char, $len);
            $this->char += $len - 1;

            $this->emitToken(array(
                'type' => self::CHARACTR,
                'data' => $char
            ));

            $this->state = 'data';
        }
    }

    private function entityDataState() {
        // Attempt to consume an entity.
        $entity = $this->entity();

        // If nothing is returned, emit a U+0026 AMPERSAND character token.
        // Otherwise, emit the character token that was returned.
        $char = (!$entity) ? '&' : $entity;
        $this->emitToken($char);

        // Finally, switch to the data state.
        $this->state = 'data';
    }

    private function tagOpenState() {
        switch($this->content_model) {
            case self::RCDATA:
            case self::CDATA:
                /* If the next input character is a U+002F SOLIDUS (/) character,
                consume it and switch to the close tag open state. If the next
                input character is not a U+002F SOLIDUS (/) character, emit a
                U+003C LESS-THAN SIGN character token and switch to the data
                state to process the next input character. */
                if($this->character($this->char + 1) === '/') {
                    $this->char++;
                    $this->state = 'closeTagOpen';

                } else {
                    $this->emitToken(array(
                        'type' => self::CHARACTR,
                        'data' => '<'
                    ));

                    $this->state = 'data';
                }
            break;

            case self::PCDATA:
                // If the content model flag is set to the PCDATA state
                // Consume the next input character:
                $this->char++;
                $char = $this->char();

                if($char === '!') {
                    /* U+0021 EXCLAMATION MARK (!)
                    Switch to the markup declaration open state. */
                    $this->state = 'markupDeclarationOpen';

                } elseif($char === '/') {
                    /* U+002F SOLIDUS (/)
                    Switch to the close tag open state. */
                    $this->state = 'closeTagOpen';

                } elseif(preg_match('/^[A-Za-z]$/', $char)) {
                    /* U+0041 LATIN LETTER A through to U+005A LATIN LETTER Z
                    Create a new start tag token, set its tag name to the lowercase
                    version of the input character (add 0x0020 to the character's code
                    point), then switch to the tag name state. (Don't emit the token
                    yet; further details will be filled in before it is emitted.) */
                    $this->token = array(
                        'name'  => strtolower($char),
                        'type'  => self::STARTTAG,
                        'attr'  => array()
                    );

                    $this->state = 'tagName';

                } elseif($char === '>') {
                    /* U+003E GREATER-THAN SIGN (>)
                    Parse error. Emit a U+003C LESS-THAN SIGN character token and a
                    U+003E GREATER-THAN SIGN character token. Switch to the data state. */
                    $this->emitToken(array(
                        'type' => self::CHARACTR,
                        'data' => '<>'
                    ));

                    $this->state = 'data';

                } elseif($char === '?') {
                    /* U+003F QUESTION MARK (?)
                    Parse error. Switch to the bogus comment state. */
                    $this->state = 'bogusComment';

                } else {
                    /* Anything else
                    Parse error. Emit a U+003C LESS-THAN SIGN character token and
                    reconsume the current input character in the data state. */
                    $this->emitToken(array(
                        'type' => self::CHARACTR,
                        'data' => '<'
                    ));

                    $this->char--;
                    $this->state = 'data';
                }
            break;
        }
    }

    private function closeTagOpenState() {
        $next_node = strtolower($this->characters('A-Za-z', $this->char + 1));
        $the_same = count($this->tree->stack) > 0 && $next_node === end($this->tree->stack)->nodeName;

        if(($this->content_model === self::RCDATA || $this->content_model === self::CDATA) &&
        (!$the_same || ($the_same && (!preg_match('/[\t\n\x0b\x0c >\/]/',
        $this->character($this->char + 1 + strlen($next_node))) || $this->EOF === $this->char)))) {
            /* If the content model flag is set to the RCDATA or CDATA states then
            examine the next few characters. If they do not match the tag name of
            the last start tag token emitted (case insensitively), or if they do but
            they are not immediately followed by one of the following characters:
                * U+0009 CHARACTER TABULATION
                * U+000A LINE FEED (LF)
                * U+000B LINE TABULATION
                * U+000C FORM FEED (FF)
                * U+0020 SPACE
                * U+003E GREATER-THAN SIGN (>)
                * U+002F SOLIDUS (/)
                * EOF
            ...then there is a parse error. Emit a U+003C LESS-THAN SIGN character
            token, a U+002F SOLIDUS character token, and switch to the data state
            to process the next input character. */
            $this->emitToken(array(
                'type' => self::CHARACTR,
                'data' => '</'
            ));

            $this->state = 'data';

        } else {
            /* Otherwise, if the content model flag is set to the PCDATA state,
            or if the next few characters do match that tag name, consume the
            next input character: */
            $this->char++;
            $char = $this->char();

            if(preg_match('/^[A-Za-z]$/', $char)) {
                /* U+0041 LATIN LETTER A through to U+005A LATIN LETTER Z
                Create a new end tag token, set its tag name to the lowercase version
                of the input character (add 0x0020 to the character's code point), then
                switch to the tag name state. (Don't emit the token yet; further details
                will be filled in before it is emitted.) */
                $this->token = array(
                    'name'  => strtolower($char),
                    'type'  => self::ENDTAG
                );

                $this->state = 'tagName';

            } elseif($char === '>') {
                /* U+003E GREATER-THAN SIGN (>)
                Parse error. Switch to the data state. */
                $this->state = 'data';

            } elseif($this->char === $this->EOF) {
                /* EOF
                Parse error. Emit a U+003C LESS-THAN SIGN character token and a U+002F
                SOLIDUS character token. Reconsume the EOF character in the data state. */
                $this->emitToken(array(
                    'type' => self::CHARACTR,
                    'data' => '</'
                ));

                $this->char--;
                $this->state = 'data';

            } else {
                /* Parse error. Switch to the bogus comment state. */
                $this->state = 'bogusComment';
            }
        }
    }

    private function tagNameState() {
        // Consume the next input character:
        $this->char++;
        $char = $this->character($this->char);

        if(preg_match('/^[\t\n\x0b\x0c ]$/', $char)) {
            /* U+0009 CHARACTER TABULATION
            U+000A LINE FEED (LF)
            U+000B LINE TABULATION
            U+000C FORM FEED (FF)
            U+0020 SPACE
            Switch to the before attribute name state. */
            $this->state = 'beforeAttributeName';

        } elseif($char === '>') {
            /* U+003E GREATER-THAN SIGN (>)
            Emit the current tag token. Switch to the data state. */
            $this->emitToken($this->token);
            $this->state = 'data';

        } elseif($this->char === $this->EOF) {
            /* EOF
            Parse error. Emit the current tag token. Reconsume the EOF
            character in the data state. */
            $this->emitToken($this->token);

            $this->char--;
            $this->state = 'data';

        } elseif($char === '/') {
            /* U+002F SOLIDUS (/)
            Parse error unless this is a permitted slash. Switch to the before
            attribute name state. */
            $this->state = 'beforeAttributeName';

        } else {
            /* Anything else
            Append the current input character to the current tag token's tag name.
            Stay in the tag name state. */
            $this->token['name'] .= strtolower($char);
            $this->state = 'tagName';
        }
    }

    private function beforeAttributeNameState() {
        // Consume the next input character:
        $this->char++;
        $char = $this->character($this->char);

        if(preg_match('/^[\t\n\x0b\x0c ]$/', $char)) {
            /* U+0009 CHARACTER TABULATION
            U+000A LINE FEED (LF)
            U+000B LINE TABULATION
            U+000C FORM FEED (FF)
            U+0020 SPACE
            Stay in the before attribute name state. */
            $this->state = 'beforeAttributeName';

        } elseif($char === '>') {
            /* U+003E GREATER-THAN SIGN (>)
            Emit the current tag token. Switch to the data state. */
            $this->emitToken($this->token);
            $this->state = 'data';

        } elseif($char === '/') {
            /* U+002F SOLIDUS (/)
            Parse error unless this is a permitted slash. Stay in the before
            attribute name state. */
            $this->state = 'beforeAttributeName';

        } elseif($this->char === $this->EOF) {
            /* EOF
            Parse error. Emit the current tag token. Reconsume the EOF
            character in the data state. */
            $this->emitToken($this->token);

            $this->char--;
            $this->state = 'data';

        } else {
            /* Anything else
            Start a new attribute in the current tag token. Set that attribute's
            name to the current input character, and its value to the empty string.
            Switch to the attribute name state. */
            $this->token['attr'][] = array(
                'name'  => strtolower($char),
                'value' => null
            );

            $this->state = 'attributeName';
        }
    }

    private function attributeNameState() {
        // Consume the next input character:
        $this->char++;
        $char = $this->character($this->char);

        if(preg_match('/^[\t\n\x0b\x0c ]$/', $char)) {
            /* U+0009 CHARACTER TABULATION
            U+000A LINE FEED (LF)
            U+000B LINE TABULATION
            U+000C FORM FEED (FF)
            U+0020 SPACE
            Stay in the before attribute name state. */
            $this->state = 'afterAttributeName';

        } elseif($char === '=') {
            /* U+003D EQUALS SIGN (=)
            Switch to the before attribute value state. */
            $this->state = 'beforeAttributeValue';

        } elseif($char === '>') {
            /* U+003E GREATER-THAN SIGN (>)
            Emit the current tag token. Switch to the data state. */
            $this->emitToken($this->token);
            $this->state = 'data';

        } elseif($char === '/' && $this->character($this->char + 1) !== '>') {
            /* U+002F SOLIDUS (/)
            Parse error unless this is a permitted slash. Switch to the before
            attribute name state. */
            $this->state = 'beforeAttributeName';

        } elseif($this->char === $this->EOF) {
            /* EOF
            Parse error. Emit the current tag token. Reconsume the EOF
            character in the data state. */
            $this->emitToken($this->token);

            $this->char--;
            $this->state = 'data';

        } else {
            /* Anything else
            Append the current input character to the current attribute's name.
            Stay in the attribute name state. */
            $last = count($this->token['attr']) - 1;
            $this->token['attr'][$last]['name'] .= strtolower($char);

            $this->state = 'attributeName';
        }
    }

    private function afterAttributeNameState() {
        // Consume the next input character:
        $this->char++;
        $char = $this->character($this->char);

        if(preg_match('/^[\t\n\x0b\x0c ]$/', $char)) {
            /* U+0009 CHARACTER TABULATION
            U+000A LINE FEED (LF)
            U+000B LINE TABULATION
            U+000C FORM FEED (FF)
            U+0020 SPACE
            Stay in the after attribute name state. */
            $this->state = 'afterAttributeName';

        } elseif($char === '=') {
            /* U+003D EQUALS SIGN (=)
            Switch to the before attribute value state. */
            $this->state = 'beforeAttributeValue';

        } elseif($char === '>') {
            /* U+003E GREATER-THAN SIGN (>)
            Emit the current tag token. Switch to the data state. */
            $this->emitToken($this->token);
            $this->state = 'data';

        } elseif($char === '/' && $this->character($this->char + 1) !== '>') {
            /* U+002F SOLIDUS (/)
            Parse error unless this is a permitted slash. Switch to the
            before attribute name state. */
            $this->state = 'beforeAttributeName';

        } elseif($this->char === $this->EOF) {
            /* EOF
            Parse error. Emit the current tag token. Reconsume the EOF
            character in the data state. */
            $this->emitToken($this->token);

            $this->char--;
            $this->state = 'data';

        } else {
            /* Anything else
            Start a new attribute in the current tag token. Set that attribute's
            name to the current input character, and its value to the empty string.
            Switch to the attribute name state. */
            $this->token['attr'][] = array(
                'name'  => strtolower($char),
                'value' => null
            );

            $this->state = 'attributeName';
        }
    }

    private function beforeAttributeValueState() {
        // Consume the next input character:
        $this->char++;
        $char = $this->character($this->char);

        if(preg_match('/^[\t\n\x0b\x0c ]$/', $char)) {
            /* U+0009 CHARACTER TABULATION
            U+000A LINE FEED (LF)
            U+000B LINE TABULATION
            U+000C FORM FEED (FF)
            U+0020 SPACE
            Stay in the before attribute value state. */
            $this->state = 'beforeAttributeValue';

        } elseif($char === '"') {
            /* U+0022 QUOTATION MARK (")
            Switch to the attribute value (double-quoted) state. */
            $this->state = 'attributeValueDoubleQuoted';

        } elseif($char === '&') {
            /* U+0026 AMPERSAND (&)
            Switch to the attribute value (unquoted) state and reconsume
            this input character. */
            $this->char--;
            $this->state = 'attributeValueUnquoted';

        } elseif($char === '\'') {
            /* U+0027 APOSTROPHE (')
            Switch to the attribute value (single-quoted) state. */
            $this->state = 'attributeValueSingleQuoted';

        } elseif($char === '>') {
            /* U+003E GREATER-THAN SIGN (>)
            Emit the current tag token. Switch to the data state. */
            $this->emitToken($this->token);
            $this->state = 'data';

        } else {
            /* Anything else
            Append the current input character to the current attribute's value.
            Switch to the attribute value (unquoted) state. */
            $last = count($this->token['attr']) - 1;
            $this->token['attr'][$last]['value'] .= $char;

            $this->state = 'attributeValueUnquoted';
        }
    }

    private function attributeValueDoubleQuotedState() {
        // Consume the next input character:
        $this->char++;
        $char = $this->character($this->char);

        if($char === '"') {
            /* U+0022 QUOTATION MARK (")
            Switch to the before attribute name state. */
            $this->state = 'beforeAttributeName';

        } elseif($char === '&') {
            /* U+0026 AMPERSAND (&)
            Switch to the entity in attribute value state. */
            $this->entityInAttributeValueState('double');

        } elseif($this->char === $this->EOF) {
            /* EOF
            Parse error. Emit the current tag token. Reconsume the character
            in the data state. */
            $this->emitToken($this->token);

            $this->char--;
            $this->state = 'data';

        } else {
            /* Anything else
            Append the current input character to the current attribute's value.
            Stay in the attribute value (double-quoted) state. */
            $last = count($this->token['attr']) - 1;
            $this->token['attr'][$last]['value'] .= $char;

            $this->state = 'attributeValueDoubleQuoted';
        }
    }

    private function attributeValueSingleQuotedState() {
        // Consume the next input character:
        $this->char++;
        $char = $this->character($this->char);

        if($char === '\'') {
            /* U+0022 QUOTATION MARK (')
            Switch to the before attribute name state. */
            $this->state = 'beforeAttributeName';

        } elseif($char === '&') {
            /* U+0026 AMPERSAND (&)
            Switch to the entity in attribute value state. */
            $this->entityInAttributeValueState('single');

        } elseif($this->char === $this->EOF) {
            /* EOF
            Parse error. Emit the current tag token. Reconsume the character
            in the data state. */
            $this->emitToken($this->token);

            $this->char--;
            $this->state = 'data';

        } else {
            /* Anything else
            Append the current input character to the current attribute's value.
            Stay in the attribute value (single-quoted) state. */
            $last = count($this->token['attr']) - 1;
            $this->token['attr'][$last]['value'] .= $char;

            $this->state = 'attributeValueSingleQuoted';
        }
    }

    private function attributeValueUnquotedState() {
        // Consume the next input character:
        $this->char++;
        $char = $this->character($this->char);

        if(preg_match('/^[\t\n\x0b\x0c ]$/', $char)) {
            /* U+0009 CHARACTER TABULATION
            U+000A LINE FEED (LF)
            U+000B LINE TABULATION
            U+000C FORM FEED (FF)
            U+0020 SPACE
            Switch to the before attribute name state. */
            $this->state = 'beforeAttributeName';

        } elseif($char === '&') {
            /* U+0026 AMPERSAND (&)
            Switch to the entity in attribute value state. */
            $this->entityInAttributeValueState('non');

        } elseif($char === '>') {
            /* U+003E GREATER-THAN SIGN (>)
            Emit the current tag token. Switch to the data state. */
            $this->emitToken($this->token);
            $this->state = 'data';

        } else {
            /* Anything else
            Append the current input character to the current attribute's value.
            Stay in the attribute value (unquoted) state. */
            $last = count($this->token['attr']) - 1;
            $this->token['attr'][$last]['value'] .= $char;

            $this->state = 'attributeValueUnquoted';
        }
    }

    private function entityInAttributeValueState() {
        // Attempt to consume an entity.
        $entity = $this->entity();

        // If nothing is returned, append a U+0026 AMPERSAND character to the
        // current attribute's value. Otherwise, emit the character token that
        // was returned.
        $char = (!$entity)
            ? '&'
            : $entity;

        $this->emitToken($char);
    }

    private function bogusCommentState() {
        /* Consume every character up to the first U+003E GREATER-THAN SIGN
        character (>) or the end of the file (EOF), whichever comes first. Emit
        a comment token whose data is the concatenation of all the characters
        starting from and including the character that caused the state machine
        to switch into the bogus comment state, up to and including the last
        consumed character before the U+003E character, if any, or up to the
        end of the file otherwise. (If the comment was started by the end of
        the file (EOF), the token is empty.) */
        $data = $this->characters('^>', $this->char);
        $this->emitToken(array(
            'data' => $data,
            'type' => self::COMMENT
        ));

        $this->char += strlen($data);

        /* Switch to the data state. */
        $this->state = 'data';

        /* If the end of the file was reached, reconsume the EOF character. */
        if($this->char === $this->EOF) {
            $this->char = $this->EOF - 1;
        }
    }

    private function markupDeclarationOpenState() {
        /* If the next two characters are both U+002D HYPHEN-MINUS (-)
        characters, consume those two characters, create a comment token whose
        data is the empty string, and switch to the comment state. */
        if($this->character($this->char + 1, 2) === '--') {
            $this->char += 2;
            $this->state = 'comment';
            $this->token = array(
                'data' => null,
                'type' => self::COMMENT
            );

        /* Otherwise if the next seven chacacters are a case-insensitive match
        for the word "DOCTYPE", then consume those characters and switch to the
        DOCTYPE state. */
        } elseif(strtolower($this->character($this->char + 1, 7)) === 'doctype') {
            $this->char += 7;
            $this->state = 'doctype';

        /* Otherwise, is is a parse error. Switch to the bogus comment state.
        The next character that is consumed, if any, is the first character
        that will be in the comment. */
        } else {
            $this->char++;
            $this->state = 'bogusComment';
        }
    }

    private function commentState() {
        /* Consume the next input character: */
        $this->char++;
        $char = $this->char();

        /* U+002D HYPHEN-MINUS (-) */
        if($char === '-') {
            /* Switch to the comment dash state  */
            $this->state = 'commentDash';

        /* EOF */
        } elseif($this->char === $this->EOF) {
            /* Parse error. Emit the comment token. Reconsume the EOF character
            in the data state. */
            $this->emitToken($this->token);
            $this->char--;
            $this->state = 'data';

        /* Anything else */
        } else {
            /* Append the input character to the comment token's data. Stay in
            the comment state. */
            $this->token['data'] .= $char;
        }
    }

    private function commentDashState() {
        /* Consume the next input character: */
        $this->char++;
        $char = $this->char();

        /* U+002D HYPHEN-MINUS (-) */
        if($char === '-') {
            /* Switch to the comment end state  */
            $this->state = 'commentEnd';

        /* EOF */
        } elseif($this->char === $this->EOF) {
            /* Parse error. Emit the comment token. Reconsume the EOF character
            in the data state. */
            $this->emitToken($this->token);
            $this->char--;
            $this->state = 'data';

        /* Anything else */
        } else {
            /* Append a U+002D HYPHEN-MINUS (-) character and the input
            character to the comment token's data. Switch to the comment state. */
            $this->token['data'] .= '-'.$char;
            $this->state = 'comment';
        }
    }

    private function commentEndState() {
        /* Consume the next input character: */
        $this->char++;
        $char = $this->char();

        if($char === '>') {
            $this->emitToken($this->token);
            $this->state = 'data';

        } elseif($char === '-') {
            $this->token['data'] .= '-';

        } elseif($this->char === $this->EOF) {
            $this->emitToken($this->token);
            $this->char--;
            $this->state = 'data';

        } else {
            $this->token['data'] .= '--'.$char;
            $this->state = 'comment';
        }
    }

    private function doctypeState() {
        /* Consume the next input character: */
        $this->char++;
        $char = $this->char();

        if(preg_match('/^[\t\n\x0b\x0c ]$/', $char)) {
            $this->state = 'beforeDoctypeName';

        } else {
            $this->char--;
            $this->state = 'beforeDoctypeName';
        }
    }

    private function beforeDoctypeNameState() {
        /* Consume the next input character: */
        $this->char++;
        $char = $this->char();

        if(preg_match('/^[\t\n\x0b\x0c ]$/', $char)) {
            // Stay in the before DOCTYPE name state.

        } elseif(preg_match('/^[a-z]$/', $char)) {
            $this->token = array(
                'name' => strtoupper($char),
                'type' => self::DOCTYPE,
                'error' => true
            );

            $this->state = 'doctypeName';

        } elseif($char === '>') {
            $this->emitToken(array(
                'name' => null,
                'type' => self::DOCTYPE,
                'error' => true
            ));

            $this->state = 'data';

        } elseif($this->char === $this->EOF) {
            $this->emitToken(array(
                'name' => null,
                'type' => self::DOCTYPE,
                'error' => true
            ));

            $this->char--;
            $this->state = 'data';

        } else {
            $this->token = array(
                'name' => $char,
                'type' => self::DOCTYPE,
                'error' => true
            );

            $this->state = 'doctypeName';
        }
    }

    private function doctypeNameState() {
        /* Consume the next input character: */
        $this->char++;
        $char = $this->char();

        if(preg_match('/^[\t\n\x0b\x0c ]$/', $char)) {
            $this->state = 'AfterDoctypeName';

        } elseif($char === '>') {
            $this->emitToken($this->token);
            $this->state = 'data';

        } elseif(preg_match('/^[a-z]$/', $char)) {
            $this->token['name'] .= strtoupper($char);

        } elseif($this->char === $this->EOF) {
            $this->emitToken($this->token);
            $this->char--;
            $this->state = 'data';

        } else {
            $this->token['name'] .= $char;
        }

        $this->token['error'] = ($this->token['name'] === 'HTML')
            ? false
            : true;
    }

    private function afterDoctypeNameState() {
        /* Consume the next input character: */
        $this->char++;
        $char = $this->char();

        if(preg_match('/^[\t\n\x0b\x0c ]$/', $char)) {
            // Stay in the DOCTYPE name state.

        } elseif($char === '>') {
            $this->emitToken($this->token);
            $this->state = 'data';

        } elseif($this->char === $this->EOF) {
            $this->emitToken($this->token);
            $this->char--;
            $this->state = 'data';

        } else {
            $this->token['error'] = true;
            $this->state = 'bogusDoctype';
        }
    }

    private function bogusDoctypeState() {
        /* Consume the next input character: */
        $this->char++;
        $char = $this->char();

        if($char === '>') {
            $this->emitToken($this->token);
            $this->state = 'data';

        } elseif($this->char === $this->EOF) {
            $this->emitToken($this->token);
            $this->char--;
            $this->state = 'data';

        } else {
            // Stay in the bogus DOCTYPE state.
        }
    }

    private function entity() {
        $start = $this->char;

        // This section defines how to consume an entity. This definition is
        // used when parsing entities in text and in attributes.

        // The behaviour depends on the identity of the next character (the
        // one immediately after the U+0026 AMPERSAND character): 

        switch($this->character($this->char + 1)) {
            // U+0023 NUMBER SIGN (#)
            case '#':

                // The behaviour further depends on the character after the
                // U+0023 NUMBER SIGN:
                switch($this->character($this->char + 1)) {
                    // U+0078 LATIN SMALL LETTER X
                    // U+0058 LATIN CAPITAL LETTER X
                    case 'x':
                    case 'X':
                        // Follow the steps below, but using the range of
                        // characters U+0030 DIGIT ZERO through to U+0039 DIGIT
                        // NINE, U+0061 LATIN SMALL LETTER A through to U+0066
                        // LATIN SMALL LETTER F, and U+0041 LATIN CAPITAL LETTER
                        // A, through to U+0046 LATIN CAPITAL LETTER F (in other
                        // words, 0-9, A-F, a-f).
                        $char = 1;
                        $char_class = '0-9A-Fa-f';
                    break;

                    // Anything else
                    default:
                        // Follow the steps below, but using the range of
                        // characters U+0030 DIGIT ZERO through to U+0039 DIGIT
                        // NINE (i.e. just 0-9).
                        $char = 0;
                        $char_class = '0-9';
                    break;
                }

                // Consume as many characters as match the range of characters
                // given above.
                $this->char++;
                $e_name = $this->characters($char_class, $this->char + $char + 1);
                $entity = $this->character($start, $this->char);
                $cond = strlen($e_name) > 0;

                // The rest of the parsing happens bellow.
            break;

            // Anything else
            default:
                // Consume the maximum number of characters possible, with the
                // consumed characters case-sensitively matching one of the
                // identifiers in the first column of the entities table.
                $e_name = $this->characters('0-9A-Za-z;', $this->char + 1);
                $len = strlen($e_name);

                for($c = 1; $c <= $len; $c++) {
                    $id = substr($e_name, 0, $c);
                    $this->char++;

                    if(in_array($id, $this->entities)) {
                        $entity = $id;
                        break;
                    }
                }

                $cond = isset($entity);
                // The rest of the parsing happens bellow.
            break;
        }

        if(!$cond) {
            // If no match can be made, then this is a parse error. No
            // characters are consumed, and nothing is returned.
            $this->char = $start;
            return false;
        }

        // Return a character token for the character corresponding to the
        // entity name (as given by the second column of the entities table).
        return html_entity_decode('&'.$entity.';', ENT_QUOTES, 'UTF-8');
    }

    private function emitToken($token) {
        $emit = $this->tree->emitToken($token);

        if(is_int($emit)) {
            $this->content_model = $emit;

        } elseif($token['type'] === self::ENDTAG) {
            $this->content_model = self::PCDATA;
        }
    }

    private function EOF() {
        $this->state = null;
        $this->tree->emitToken(array(
            'type' => self::EOF
        ));
    }
}

class HTML5TreeConstructer {
    public $stack = array();

    private $phase;
    private $mode;
    private $dom;
    private $foster_parent = null;
    private $a_formatting  = array();

    private $head_pointer = null;
    private $form_pointer = null;

    private $scoping = array('button','caption','html','marquee','object','table','td','th');
    private $formatting = array('a','b','big','em','font','i','nobr','s','small','strike','strong','tt','u');
    private $special = array('address','area','base','basefont','bgsound',
    'blockquote','body','br','center','col','colgroup','dd','dir','div','dl',
    'dt','embed','fieldset','form','frame','frameset','h1','h2','h3','h4','h5',
    'h6','head','hr','iframe','image','img','input','isindex','li','link',
    'listing','menu','meta','noembed','noframes','noscript','ol','optgroup',
    'option','p','param','plaintext','pre','script','select','spacer','style',
    'tbody','textarea','tfoot','thead','title','tr','ul','wbr');

    // The different phases.
    const INIT_PHASE = 0;
    const ROOT_PHASE = 1;
    const MAIN_PHASE = 2;
    const END_PHASE  = 3;

    // The different insertion modes for the main phase.
    const BEFOR_HEAD = 0;
    const IN_HEAD    = 1;
    const AFTER_HEAD = 2;
    const IN_BODY    = 3;
    const IN_TABLE   = 4;
    const IN_CAPTION = 5;
    const IN_CGROUP  = 6;
    const IN_TBODY   = 7;
    const IN_ROW     = 8;
    const IN_CELL    = 9;
    const IN_SELECT  = 10;
    const AFTER_BODY = 11;
    const IN_FRAME   = 12;
    const AFTR_FRAME = 13;

    // The different types of elements.
    const SPECIAL    = 0;
    const SCOPING    = 1;
    const FORMATTING = 2;
    const PHRASING   = 3;

    const MARKER     = 0;

    public function __construct() {
        $this->phase = self::INIT_PHASE;
        $this->mode = self::BEFOR_HEAD;
        $this->dom = new DOMDocument;

        $this->dom->encoding = 'UTF-8';
        $this->dom->preserveWhiteSpace = true;
        $this->dom->substituteEntities = true;
        $this->dom->strictErrorChecking = false;
    }

    // Process tag tokens
    public function emitToken($token) {
        switch($this->phase) {
            case self::INIT_PHASE: return $this->initPhase($token); break;
            case self::ROOT_PHASE: return $this->rootElementPhase($token); break;
            case self::MAIN_PHASE: return $this->mainPhase($token); break;
            case self::END_PHASE : return $this->trailingEndPhase($token); break;
        }
    }

    private function initPhase($token) {
        /* Initially, the tree construction stage must handle each token
        emitted from the tokenisation stage as follows: */

        /* A DOCTYPE token that is marked as being in error
        A comment token
        A start tag token
        An end tag token
        A character token that is not one of one of U+0009 CHARACTER TABULATION,
            U+000A LINE FEED (LF), U+000B LINE TABULATION, U+000C FORM FEED (FF),
            or U+0020 SPACE
        An end-of-file token */
        if((isset($token['error']) && $token['error']) ||
        $token['type'] === HTML5::COMMENT ||
        $token['type'] === HTML5::STARTTAG ||
        $token['type'] === HTML5::ENDTAG ||
        $token['type'] === HTML5::EOF ||
        ($token['type'] === HTML5::CHARACTR && isset($token['data']) &&
        !preg_match('/^[\t\n\x0b\x0c ]+$/', $token['data']))) {
            /* This specification does not define how to handle this case. In
            particular, user agents may ignore the entirety of this specification
            altogether for such documents, and instead invoke special parse modes
            with a greater emphasis on backwards compatibility. */

            $this->phase = self::ROOT_PHASE;
            return $this->rootElementPhase($token);

        /* A DOCTYPE token marked as being correct */
        } elseif(isset($token['error']) && !$token['error']) {
            /* Append a DocumentType node to the Document  node, with the name
            attribute set to the name given in the DOCTYPE token (which will be
            "HTML"), and the other attributes specific to DocumentType objects
            set to null, empty lists, or the empty string as appropriate. */
            $doctype = new DOMDocumentType(null, null, 'HTML');

            /* Then, switch to the root element phase of the tree construction
            stage. */
            $this->phase = self::ROOT_PHASE;

        /* A character token that is one of one of U+0009 CHARACTER TABULATION,
        U+000A LINE FEED (LF), U+000B LINE TABULATION, U+000C FORM FEED (FF),
        or U+0020 SPACE */
        } elseif(isset($token['data']) && preg_match('/^[\t\n\x0b\x0c ]+$/',
        $token['data'])) {
            /* Append that character  to the Document node. */
            $text = $this->dom->createTextNode($token['data']);
            $this->dom->appendChild($text);
        }
    }

    private function rootElementPhase($token) {
        /* After the initial phase, as each token is emitted from the tokenisation
        stage, it must be processed as described in this section. */

        /* A DOCTYPE token */
        if($token['type'] === HTML5::DOCTYPE) {
            // Parse error. Ignore the token.

        /* A comment token */
        } elseif($token['type'] === HTML5::COMMENT) {
            /* Append a Comment node to the Document object with the data
            attribute set to the data given in the comment token. */
            $comment = $this->dom->createComment($token['data']);
            $this->dom->appendChild($comment);

        /* A character token that is one of one of U+0009 CHARACTER TABULATION,
        U+000A LINE FEED (LF), U+000B LINE TABULATION, U+000C FORM FEED (FF),
        or U+0020 SPACE */
        } elseif($token['type'] === HTML5::CHARACTR &&
        preg_match('/^[\t\n\x0b\x0c ]+$/', $token['data'])) {
            /* Append that character  to the Document node. */
            $text = $this->dom->createTextNode($token['data']);
            $this->dom->appendChild($text);

        /* A character token that is not one of U+0009 CHARACTER TABULATION,
            U+000A LINE FEED (LF), U+000B LINE TABULATION, U+000C FORM FEED
            (FF), or U+0020 SPACE
        A start tag token
        An end tag token
        An end-of-file token */
        } elseif(($token['type'] === HTML5::CHARACTR &&
        !preg_match('/^[\t\n\x0b\x0c ]+$/', $token['data'])) ||
        $token['type'] === HTML5::STARTTAG ||
        $token['type'] === HTML5::ENDTAG ||
        $token['type'] === HTML5::EOF) {
            /* Create an HTMLElement node with the tag name html, in the HTML
            namespace. Append it to the Document object. Switch to the main
            phase and reprocess the current token. */
            $html = $this->dom->createElement('html');
            $this->dom->appendChild($html);
            $this->stack[] = $html;

            $this->phase = self::MAIN_PHASE;
            return $this->mainPhase($token);
        }
    }

    private function mainPhase($token) {
        /* Tokens in the main phase must be handled as follows: */

        /* A DOCTYPE token */
        if($token['type'] === HTML5::DOCTYPE) {
            // Parse error. Ignore the token.

        /* A start tag token with the tag name "html" */
        } elseif($token['type'] === HTML5::STARTTAG && $token['name'] === 'html') {
            /* If this start tag token was not the first start tag token, then
            it is a parse error. */

            /* For each attribute on the token, check to see if the attribute
            is already present on the top element of the stack of open elements.
            If it is not, add the attribute and its corresponding value to that
            element. */
            foreach($token['attr'] as $attr) {
                if(!$this->stack[0]->hasAttribute($attr['name'])) {
                    $this->stack[0]->setAttribute($attr['name'], $attr['value']);
                }
            }

        /* An end-of-file token */
        } elseif($token['type'] === HTML5::EOF) {
            /* Generate implied end tags. */
            $this->generateImpliedEndTags();

        /* Anything else. */
        } else {
            /* Depends on the insertion mode: */
            switch($this->mode) {
                case self::BEFOR_HEAD: return $this->beforeHead($token); break;
                case self::IN_HEAD:    return $this->inHead($token); break;
                case self::AFTER_HEAD: return $this->afterHead($token); break;
                case self::IN_BODY:    return $this->inBody($token); break;
                case self::IN_TABLE:   return $this->inTable($token); break;
                case self::IN_CAPTION: return $this->inCaption($token); break;
                case self::IN_CGROUP:  return $this->inColumnGroup($token); break;
                case self::IN_TBODY:   return $this->inTableBody($token); break;
                case self::IN_ROW:     return $this->inRow($token); break;
                case self::IN_CELL:    return $this->inCell($token); break;
                case self::IN_SELECT:  return $this->inSelect($token); break;
                case self::AFTER_BODY: return $this->afterBody($token); break;
                case self::IN_FRAME:   return $this->inFrameset($token); break;
                case self::AFTR_FRAME: return $this->afterFrameset($token); break;
                case self::END_PHASE:  return $this->trailingEndPhase($token); break;
            }
        }
    }

    private function beforeHead($token) {
        /* Handle the token as follows: */

        /* A character token that is one of one of U+0009 CHARACTER TABULATION,
        U+000A LINE FEED (LF), U+000B LINE TABULATION, U+000C FORM FEED (FF),
        or U+0020 SPACE */
        if($token['type'] === HTML5::CHARACTR &&
        preg_match('/^[\t\n\x0b\x0c ]+$/', $token['data'])) {
            /* Append the character to the current node. */
            $this->insertText($token['data']);

        /* A comment token */
        } elseif($token['type'] === HTML5::COMMENT) {
            /* Append a Comment node to the current node with the data attribute
            set to the data given in the comment token. */
            $this->insertComment($token['data']);

        /* A start tag token with the tag name "head" */
        } elseif($token['type'] === HTML5::STARTTAG && $token['name'] === 'head') {
            /* Create an element for the token, append the new element to the
            current node and push it onto the stack of open elements. */
            $element = $this->insertElement($token);

            /* Set the head element pointer to this new element node. */
            $this->head_pointer = $element;

            /* Change the insertion mode to "in head". */
            $this->mode = self::IN_HEAD;

        /* A start tag token whose tag name is one of: "base", "link", "meta",
        "script", "style", "title". Or an end tag with the tag name "html".
        Or a character token that is not one of U+0009 CHARACTER TABULATION,
        U+000A LINE FEED (LF), U+000B LINE TABULATION, U+000C FORM FEED (FF),
        or U+0020 SPACE. Or any other start tag token */
        } elseif($token['type'] === HTML5::STARTTAG ||
        ($token['type'] === HTML5::ENDTAG && $token['name'] === 'html') ||
        ($token['type'] === HTML5::CHARACTR && !preg_match('/^[\t\n\x0b\x0c ]$/',
        $token['data']))) {
            /* Act as if a start tag token with the tag name "head" and no
            attributes had been seen, then reprocess the current token. */
            $this->beforeHead(array(
                'name' => 'head',
                'type' => HTML5::STARTTAG,
                'attr' => array()
            ));

            return $this->inHead($token);

        /* Any other end tag */
        } elseif($token['type'] === HTML5::ENDTAG) {
            /* Parse error. Ignore the token. */
        }
    }

    private function inHead($token) {
        /* Handle the token as follows: */

        /* A character token that is one of one of U+0009 CHARACTER TABULATION,
        U+000A LINE FEED (LF), U+000B LINE TABULATION, U+000C FORM FEED (FF),
        or U+0020 SPACE.

        THIS DIFFERS FROM THE SPEC: If the current node is either a title, style
        or script element, append the character to the current node regardless
        of its content. */
        if(($token['type'] === HTML5::CHARACTR &&
        preg_match('/^[\t\n\x0b\x0c ]+$/', $token['data'])) || (
        $token['type'] === HTML5::CHARACTR && in_array(end($this->stack)->nodeName,
        array('title', 'style', 'script')))) {
            /* Append the character to the current node. */
            $this->insertText($token['data']);

        /* A comment token */
        } elseif($token['type'] === HTML5::COMMENT) {
            /* Append a Comment node to the current node with the data attribute
            set to the data given in the comment token. */
            $this->insertComment($token['data']);

        } elseif($token['type'] === HTML5::ENDTAG &&
        in_array($token['name'], array('title', 'style', 'script'))) {
            array_pop($this->stack);
            return HTML5::PCDATA;

        /* A start tag with the tag name "title" */
        } elseif($token['type'] === HTML5::STARTTAG && $token['name'] === 'title') {
            /* Create an element for the token and append the new element to the
            node pointed to by the head element pointer, or, if that is null
            (innerHTML case), to the current node. */
            if($this->head_pointer !== null) {
                $element = $this->insertElement($token, false);
                $this->head_pointer->appendChild($element);

            } else {
                $element = $this->insertElement($token);
            }

            /* Switch the tokeniser's content model flag  to the RCDATA state. */
            return HTML5::RCDATA;

        /* A start tag with the tag name "style" */
        } elseif($token['type'] === HTML5::STARTTAG && $token['name'] === 'style') {
            /* Create an element for the token and append the new element to the
            node pointed to by the head element pointer, or, if that is null
            (innerHTML case), to the current node. */
            if($this->head_pointer !== null) {
                $element = $this->insertElement($token, false);
                $this->head_pointer->appendChild($element);

            } else {
                $this->insertElement($token);
            }

            /* Switch the tokeniser's content model flag  to the CDATA state. */
            return HTML5::CDATA;

        /* A start tag with the tag name "script" */
        } elseif($token['type'] === HTML5::STARTTAG && $token['name'] === 'script') {
            /* Create an element for the token. */
            $element = $this->insertElement($token, false);
            $this->head_pointer->appendChild($element);

            /* Switch the tokeniser's content model flag  to the CDATA state. */
            return HTML5::CDATA;

        /* A start tag with the tag name "base", "link", or "meta" */
        } elseif($token['type'] === HTML5::STARTTAG && in_array($token['name'],
        array('base', 'link', 'meta'))) {
            /* Create an element for the token and append the new element to the
            node pointed to by the head element pointer, or, if that is null
            (innerHTML case), to the current node. */
            if($this->head_pointer !== null) {
                $element = $this->insertElement($token, false);
                $this->head_pointer->appendChild($element);
                array_pop($this->stack);

            } else {
                $this->insertElement($token);
            }

        /* An end tag with the tag name "head" */
        } elseif($token['type'] === HTML5::ENDTAG && $token['name'] === 'head') {
            /* If the current node is a head element, pop the current node off
            the stack of open elements. */
            if($this->head_pointer->isSameNode(end($this->stack))) {
                array_pop($this->stack);

            /* Otherwise, this is a parse error. */
            } else {
                // k
            }

            /* Change the insertion mode to "after head". */
            $this->mode = self::AFTER_HEAD;

        /* A start tag with the tag name "head" or an end tag except "html". */
        } elseif(($token['type'] === HTML5::STARTTAG && $token['name'] === 'head') ||
        ($token['type'] === HTML5::ENDTAG && $token['name'] !== 'html')) {
            // Parse error. Ignore the token.

        /* Anything else */
        } else {
            /* If the current node is a head element, act as if an end tag
            token with the tag name "head" had been seen. */
            if($this->head_pointer->isSameNode(end($this->stack))) {
                $this->inHead(array(
                    'name' => 'head',
                    'type' => HTML5::ENDTAG
                ));

            /* Otherwise, change the insertion mode to "after head". */
            } else {
                $this->mode = self::AFTER_HEAD;
            }

            /* Then, reprocess the current token. */
            return $this->afterHead($token);
        }
    }

    private function afterHead($token) {
        /* Handle the token as follows: */

        /* A character token that is one of one of U+0009 CHARACTER TABULATION,
        U+000A LINE FEED (LF), U+000B LINE TABULATION, U+000C FORM FEED (FF),
        or U+0020 SPACE */
        if($token['type'] === HTML5::CHARACTR &&
        preg_match('/^[\t\n\x0b\x0c ]+$/', $token['data'])) {
            /* Append the character to the current node. */
            $this->insertText($token['data']);

        /* A comment token */
        } elseif($token['type'] === HTML5::COMMENT) {
            /* Append a Comment node to the current node with the data attribute
            set to the data given in the comment token. */
            $this->insertComment($token['data']);

        /* A start tag token with the tag name "body" */
        } elseif($token['type'] === HTML5::STARTTAG && $token['name'] === 'body') {
            /* Insert a body element for the token. */
            $this->insertElement($token);

            /* Change the insertion mode to "in body". */
            $this->mode = self::IN_BODY;

        /* A start tag token with the tag name "frameset" */
        } elseif($token['type'] === HTML5::STARTTAG && $token['name'] === 'frameset') {
            /* Insert a frameset element for the token. */
            $this->insertElement($token);

            /* Change the insertion mode to "in frameset". */
            $this->mode = self::IN_FRAME;

        /* A start tag token whose tag name is one of: "base", "link", "meta",
        "script", "style", "title" */
        } elseif($token['type'] === HTML5::STARTTAG && in_array($token['name'],
        array('base', 'link', 'meta', 'script', 'style', 'title'))) {
            /* Parse error. Switch the insertion mode back to "in head" and
            reprocess the token. */
            $this->mode = self::IN_HEAD;
            return $this->inHead($token);

        /* Anything else */
        } else {
            /* Act as if a start tag token with the tag name "body" and no
            attributes had been seen, and then reprocess the current token. */
            $this->afterHead(array(
                'name' => 'body',
                'type' => HTML5::STARTTAG,
                'attr' => array()
            ));

            return $this->inBody($token);
        }
    }

    private function inBody($token) {
        /* Handle the token as follows: */

        switch($token['type']) {
            /* A character token */
            case HTML5::CHARACTR:
                /* Reconstruct the active formatting elements, if any. */
                $this->reconstructActiveFormattingElements();

                /* Append the token's character to the current node. */
                $this->insertText($token['data']);
            break;

            /* A comment token */
            case HTML5::COMMENT:
                /* Append a Comment node to the current node with the data
                attribute set to the data given in the comment token. */
                $this->insertComment($token['data']);
            break;

            case HTML5::STARTTAG:
            switch($token['name']) {
                /* A start tag token whose tag name is one of: "script",
                "style" */
                case 'script': case 'style':
                    /* Process the token as if the insertion mode had been "in
                    head". */
                    return $this->inHead($token);
                break;

                /* A start tag token whose tag name is one of: "base", "link",
                "meta", "title" */
                case 'base': case 'link': case 'meta': case 'title':
                    /* Parse error. Process the token as if the insertion mode
                    had    been "in head". */
                    return $this->inHead($token);
                break;

                /* A start tag token with the tag name "body" */
                case 'body':
                    /* Parse error. If the second element on the stack of open
                    elements is not a body element, or, if the stack of open
                    elements has only one node on it, then ignore the token.
                    (innerHTML case) */
                    if(count($this->stack) === 1 || $this->stack[1]->nodeName !== 'body') {
                        // Ignore

                    /* Otherwise, for each attribute on the token, check to see
                    if the attribute is already present on the body element (the
                    second element)    on the stack of open elements. If it is not,
                    add the attribute and its corresponding value to that
                    element. */
                    } else {
                        foreach($token['attr'] as $attr) {
                            if(!$this->stack[1]->hasAttribute($attr['name'])) {
                                $this->stack[1]->setAttribute($attr['name'], $attr['value']);
                            }
                        }
                    }
                break;

                /* A start tag whose tag name is one of: "address",
                "blockquote", "center", "dir", "div", "dl", "fieldset",
                "listing", "menu", "ol", "p", "ul" */
                case 'address': case 'blockquote': case 'center': case 'dir':
                case 'div': case 'dl': case 'fieldset': case 'listing':
                case 'menu': case 'ol': case 'p': case 'ul':
                    /* If the stack of open elements has a p element in scope,
                    then act as if an end tag with the tag name p had been
                    seen. */
                    if($this->elementInScope('p')) {
                        $this->emitToken(array(
                            'name' => 'p',
                            'type' => HTML5::ENDTAG
                        ));
                    }

                    /* Insert an HTML element for the token. */
                    $this->insertElement($token);
                break;

                /* A start tag whose tag name is "form" */
                case 'form':
                    /* If the form element pointer is not null, ignore the
                    token with a parse error. */
                    if($this->form_pointer !== null) {
                        // Ignore.

                    /* Otherwise: */
                    } else {
                        /* If the stack of open elements has a p element in
                        scope, then act as if an end tag with the tag name p
                        had been seen. */
                        if($this->elementInScope('p')) {
                            $this->emitToken(array(
                                'name' => 'p',
                                'type' => HTML5::ENDTAG
                            ));
                        }

                        /* Insert an HTML element for the token, and set the
                        form element pointer to point to the element created. */
                        $element = $this->insertElement($token);
                        $this->form_pointer = $element;
                    }
                break;

                /* A start tag whose tag name is "li", "dd" or "dt" */
                case 'li': case 'dd': case 'dt':
                    /* If the stack of open elements has a p  element in scope,
                    then act as if an end tag with the tag name p had been
                    seen. */
                    if($this->elementInScope('p')) {
                        $this->emitToken(array(
                            'name' => 'p',
                            'type' => HTML5::ENDTAG
                        ));
                    }

                    $stack_length = count($this->stack) - 1;

                    for($n = $stack_length; 0 <= $n; $n--) {
                        /* 1. Initialise node to be the current node (the
                        bottommost node of the stack). */
                        $stop = false;
                        $node = $this->stack[$n];
                        $cat  = $this->getElementCategory($node->tagName);

                        /* 2. If node is an li, dd or dt element, then pop all
                        the    nodes from the current node up to node, including
                        node, then stop this algorithm. */
                        if($token['name'] === $node->tagName ||    ($token['name'] !== 'li'
                        && ($node->tagName === 'dd' || $node->tagName === 'dt'))) {
                            for($x = $stack_length; $x >= $n ; $x--) {
                                array_pop($this->stack);
                            }

                            break;
                        }

                        /* 3. If node is not in the formatting category, and is
                        not    in the phrasing category, and is not an address or
                        div element, then stop this algorithm. */
                        if($cat !== self::FORMATTING && $cat !== self::PHRASING &&
                        $node->tagName !== 'address' && $node->tagName !== 'div') {
                            break;
                        }
                    }

                    /* Finally, insert an HTML element with the same tag
                    name as the    token's. */
                    $this->insertElement($token);
                break;

                /* A start tag token whose tag name is "plaintext" */
                case 'plaintext':
                    /* If the stack of open elements has a p  element in scope,
                    then act as if an end tag with the tag name p had been
                    seen. */
                    if($this->elementInScope('p')) {
                        $this->emitToken(array(
                            'name' => 'p',
                            'type' => HTML5::ENDTAG
                        ));
                    }

                    /* Insert an HTML element for the token. */
                    $this->insertElement($token);

                    return HTML5::PLAINTEXT;
                break;

                /* A start tag whose tag name is one of: "h1", "h2", "h3", "h4",
                "h5", "h6" */
                case 'h1': case 'h2': case 'h3': case 'h4': case 'h5': case 'h6':
                    /* If the stack of open elements has a p  element in scope,
                    then act as if an end tag with the tag name p had been seen. */
                    if($this->elementInScope('p')) {
                        $this->emitToken(array(
                            'name' => 'p',
                            'type' => HTML5::ENDTAG
                        ));
                    }

                    /* If the stack of open elements has in scope an element whose
                    tag name is one of "h1", "h2", "h3", "h4", "h5", or "h6", then
                    this is a parse error; pop elements from the stack until an
                    element with one of those tag names has been popped from the
                    stack. */
                    while($this->elementInScope(array('h1', 'h2', 'h3', 'h4', 'h5', 'h6'))) {
                        array_pop($this->stack);
                    }

                    /* Insert an HTML element for the token. */
                    $this->insertElement($token);
                break;

                /* A start tag whose tag name is "a" */
                case 'a':
                    /* If the list of active formatting elements contains
                    an element whose tag name is "a" between the end of the
                    list and the last marker on the list (or the start of
                    the list if there is no marker on the list), then this
                    is a parse error; act as if an end tag with the tag name
                    "a" had been seen, then remove that element from the list
                    of active formatting elements and the stack of open
                    elements if the end tag didn't already remove it (it
                    might not have if the element is not in table scope). */
                    $leng = count($this->a_formatting);

                    for($n = $leng - 1; $n >= 0; $n--) {
                        if($this->a_formatting[$n] === self::MARKER) {
                            break;

                        } elseif($this->a_formatting[$n]->nodeName === 'a') {
                            $this->emitToken(array(
                                'name' => 'a',
                                'type' => HTML5::ENDTAG
                            ));
                            break;
                        }
                    }

                    /* Reconstruct the active formatting elements, if any. */
                    $this->reconstructActiveFormattingElements();

                    /* Insert an HTML element for the token. */
                    $el = $this->insertElement($token);

                    /* Add that element to the list of active formatting
                    elements. */
                    $this->a_formatting[] = $el;
                break;

                /* A start tag whose tag name is one of: "b", "big", "em", "font",
                "i", "nobr", "s", "small", "strike", "strong", "tt", "u" */
                case 'b': case 'big': case 'em': case 'font': case 'i':
                case 'nobr': case 's': case 'small': case 'strike':
                case 'strong': case 'tt': case 'u':
                    /* Reconstruct the active formatting elements, if any. */
                    $this->reconstructActiveFormattingElements();

                    /* Insert an HTML element for the token. */
                    $el = $this->insertElement($token);

                    /* Add that element to the list of active formatting
                    elements. */
                    $this->a_formatting[] = $el;
                break;

                /* A start tag token whose tag name is "button" */
                case 'button':
                    /* If the stack of open elements has a button element in scope,
                    then this is a parse error; act as if an end tag with the tag
                    name "button" had been seen, then reprocess the token. (We don't
                    do that. Unnecessary.) */
                    if($this->elementInScope('button')) {
                        $this->inBody(array(
                            'name' => 'button',
                            'type' => HTML5::ENDTAG
                        ));
                    }

                    /* Reconstruct the active formatting elements, if any. */
                    $this->reconstructActiveFormattingElements();

                    /* Insert an HTML element for the token. */
                    $this->insertElement($token);

                    /* Insert a marker at the end of the list of active
                    formatting elements. */
                    $this->a_formatting[] = self::MARKER;
                break;

                /* A start tag token whose tag name is one of: "marquee", "object" */
                case 'marquee': case 'object':
                    /* Reconstruct the active formatting elements, if any. */
                    $this->reconstructActiveFormattingElements();

                    /* Insert an HTML element for the token. */
                    $this->insertElement($token);

                    /* Insert a marker at the end of the list of active
                    formatting elements. */
                    $this->a_formatting[] = self::MARKER;
                break;

                /* A start tag token whose tag name is "xmp" */
                case 'xmp':
                    /* Reconstruct the active formatting elements, if any. */
                    $this->reconstructActiveFormattingElements();

                    /* Insert an HTML element for the token. */
                    $this->insertElement($token);

                    /* Switch the content model flag to the CDATA state. */
                    return HTML5::CDATA;
                break;

                /* A start tag whose tag name is "table" */
                case 'table':
                    /* If the stack of open elements has a p element in scope,
                    then act as if an end tag with the tag name p had been seen. */
                    if($this->elementInScope('p')) {
                        $this->emitToken(array(
                            'name' => 'p',
                            'type' => HTML5::ENDTAG
                        ));
                    }

                    /* Insert an HTML element for the token. */
                    $this->insertElement($token);

                    /* Change the insertion mode to "in table". */
                    $this->mode = self::IN_TABLE;
                break;

                /* A start tag whose tag name is one of: "area", "basefont",
                "bgsound", "br", "embed", "img", "param", "spacer", "wbr" */
                case 'area': case 'basefont': case 'bgsound': case 'br':
                case 'embed': case 'img': case 'param': case 'spacer':
                case 'wbr':
                    /* Reconstruct the active formatting elements, if any. */
                    $this->reconstructActiveFormattingElements();

                    /* Insert an HTML element for the token. */
                    $this->insertElement($token);

                    /* Immediately pop the current node off the stack of open elements. */
                    array_pop($this->stack);
                break;

                /* A start tag whose tag name is "hr" */
                case 'hr':
                    /* If the stack of open elements has a p element in scope,
                    then act as if an end tag with the tag name p had been seen. */
                    if($this->elementInScope('p')) {
                        $this->emitToken(array(
                            'name' => 'p',
                            'type' => HTML5::ENDTAG
                        ));
                    }

                    /* Insert an HTML element for the token. */
                    $this->insertElement($token);

                    /* Immediately pop the current node off the stack of open elements. */
                    array_pop($this->stack);
                break;

                /* A start tag whose tag name is "image" */
                case 'image':
                    /* Parse error. Change the token's tag name to "img" and
                    reprocess it. (Don't ask.) */
                    $token['name'] = 'img';
                    return $this->inBody($token);
                break;

                /* A start tag whose tag name is "input" */
                case 'input':
                    /* Reconstruct the active formatting elements, if any. */
                    $this->reconstructActiveFormattingElements();

                    /* Insert an input element for the token. */
                    $element = $this->insertElement($token, false);

                    /* If the form element pointer is not null, then associate the
                    input element with the form element pointed to by the form
                    element pointer. */
                    $this->form_pointer !== null
                        ? $this->form_pointer->appendChild($element)
                        : end($this->stack)->appendChild($element);

                    /* Pop that input element off the stack of open elements. */
                    array_pop($this->stack);
                break;

                /* A start tag whose tag name is "isindex" */
                case 'isindex':
                    /* Parse error. */
                    // w/e

                    /* If the form element pointer is not null,
                    then ignore the token. */
                    if($this->form_pointer === null) {
                        /* Act as if a start tag token with the tag name "form" had
                        been seen. */
                        $this->inBody(array(
                            'name' => 'body',
                            'type' => HTML5::STARTTAG,
                            'attr' => array()
                        ));

                        /* Act as if a start tag token with the tag name "hr" had
                        been seen. */
                        $this->inBody(array(
                            'name' => 'hr',
                            'type' => HTML5::STARTTAG,
                            'attr' => array()
                        ));

                        /* Act as if a start tag token with the tag name "p" had
                        been seen. */
                        $this->inBody(array(
                            'name' => 'p',
                            'type' => HTML5::STARTTAG,
                            'attr' => array()
                        ));

                        /* Act as if a start tag token with the tag name "label"
                        had been seen. */
                        $this->inBody(array(
                            'name' => 'label',
                            'type' => HTML5::STARTTAG,
                            'attr' => array()
                        ));

                        /* Act as if a stream of character tokens had been seen. */
                        $this->insertText('This is a searchable index. '.
                        'Insert your search keywords here: ');

                        /* Act as if a start tag token with the tag name "input"
                        had been seen, with all the attributes from the "isindex"
                        token, except with the "name" attribute set to the value
                        "isindex" (ignoring any explicit "name" attribute). */
                        $attr = $token['attr'];
                        $attr[] = array('name' => 'name', 'value' => 'isindex');

                        $this->inBody(array(
                            'name' => 'input',
                            'type' => HTML5::STARTTAG,
                            'attr' => $attr
                        ));

                        /* Act as if a stream of character tokens had been seen
                        (see below for what they should say). */
                        $this->insertText('This is a searchable index. '.
                        'Insert your search keywords here: ');

                        /* Act as if an end tag token with the tag name "label"
                        had been seen. */
                        $this->inBody(array(
                            'name' => 'label',
                            'type' => HTML5::ENDTAG
                        ));

                        /* Act as if an end tag token with the tag name "p" had
                        been seen. */
                        $this->inBody(array(
                            'name' => 'p',
                            'type' => HTML5::ENDTAG
                        ));

                        /* Act as if a start tag token with the tag name "hr" had
                        been seen. */
                        $this->inBody(array(
                            'name' => 'hr',
                            'type' => HTML5::ENDTAG
                        ));

                        /* Act as if an end tag token with the tag name "form" had
                        been seen. */
                        $this->inBody(array(
                            'name' => 'form',
                            'type' => HTML5::ENDTAG
                        ));
                    }
                break;

                /* A start tag whose tag name is "textarea" */
                case 'textarea':
                    $this->insertElement($token);

                    /* Switch the tokeniser's content model flag to the
                    RCDATA state. */
                    return HTML5::RCDATA;
                break;

                /* A start tag whose tag name is one of: "iframe", "noembed",
                "noframes" */
                case 'iframe': case 'noembed': case 'noframes':
                    $this->insertElement($token);

                    /* Switch the tokeniser's content model flag to the CDATA state. */
                    return HTML5::CDATA;
                break;

                /* A start tag whose tag name is "select" */
                case 'select':
                    /* Reconstruct the active formatting elements, if any. */
                    $this->reconstructActiveFormattingElements();

                    /* Insert an HTML element for the token. */
                    $this->insertElement($token);

                    /* Change the insertion mode to "in select". */
                    $this->mode = self::IN_SELECT;
                break;

                /* A start or end tag whose tag name is one of: "caption", "col",
                "colgroup", "frame", "frameset", "head", "option", "optgroup",
                "tbody", "td", "tfoot", "th", "thead", "tr". */
                case 'caption': case 'col': case 'colgroup': case 'frame':
                case 'frameset': case 'head': case 'option': case 'optgroup':
                case 'tbody': case 'td': case 'tfoot': case 'th': case 'thead':
                case 'tr':
                    // Parse error. Ignore the token.
                break;

                /* A start or end tag whose tag name is one of: "event-source",
                "section", "nav", "article", "aside", "header", "footer",
                "datagrid", "command" */
                case 'event-source': case 'section': case 'nav': case 'article':
                case 'aside': case 'header': case 'footer': case 'datagrid':
                case 'command':
                    // Work in progress!
                break;

                /* A start tag token not covered by the previous entries */
                default:
                    /* Reconstruct the active formatting elements, if any. */
                    $this->reconstructActiveFormattingElements();

                    $this->insertElement($token);
                break;
            }
            break;

            case HTML5::ENDTAG:
            switch($token['name']) {
                /* An end tag with the tag name "body" */
                case 'body':
                    /* If the second element in the stack of open elements is
                    not a body element, this is a parse error. Ignore the token.
                    (innerHTML case) */
                    if(count($this->stack) < 2 || $this->stack[1]->nodeName !== 'body') {
                        // Ignore.

                    /* If the current node is not the body element, then this
                    is a parse error. */
                    } elseif(end($this->stack)->nodeName !== 'body') {
                        // Parse error.
                    }

                    /* Change the insertion mode to "after body". */
                    $this->mode = self::AFTER_BODY;
                break;

                /* An end tag with the tag name "html" */
                case 'html':
                    /* Act as if an end tag with tag name "body" had been seen,
                    then, if that token wasn't ignored, reprocess the current
                    token. */
                    $this->inBody(array(
                        'name' => 'body',
                        'type' => HTML5::ENDTAG
                    ));

                    return $this->afterBody($token);
                break;

                /* An end tag whose tag name is one of: "address", "blockquote",
                "center", "dir", "div", "dl", "fieldset", "listing", "menu",
                "ol", "pre", "ul" */
                case 'address': case 'blockquote': case 'center': case 'dir':
                case 'div': case 'dl': case 'fieldset': case 'listing':
                case 'menu': case 'ol': case 'pre': case 'ul':
                    /* If the stack of open elements has an element in scope
                    with the same tag name as that of the token, then generate
                    implied end tags. */
                    if($this->elementInScope($token['name'])) {
                        $this->generateImpliedEndTags();

                        /* Now, if the current node is not an element with
                        the same tag name as that of the token, then this
                        is a parse error. */
                        // w/e

                        /* If the stack of open elements has an element in
                        scope with the same tag name as that of the token,
                        then pop elements from this stack until an element
                        with that tag name has been popped from the stack. */
                        for($n = count($this->stack) - 1; $n >= 0; $n--) {
                            if($this->stack[$n]->nodeName === $token['name']) {
                                $n = -1;
                            }

                            array_pop($this->stack);
                        }
                    }
                break;

                /* An end tag whose tag name is "form" */
                case 'form':
                    /* If the stack of open elements has an element in scope
                    with the same tag name as that of the token, then generate
                    implied    end tags. */
                    if($this->elementInScope($token['name'])) {
                        $this->generateImpliedEndTags();

                    } 

                    if(end($this->stack)->nodeName !== $token['name']) {
                        /* Now, if the current node is not an element with the
                        same tag name as that of the token, then this is a parse
                        error. */
                        // w/e

                    } else {
                        /* Otherwise, if the current node is an element with
                        the same tag name as that of the token pop that element
                        from the stack. */
                        array_pop($this->stack);
                    }

                    /* In any case, set the form element pointer to null. */
                    $this->form_pointer = null;
                break;

                /* An end tag whose tag name is "p" */
                case 'p':
                    /* If the stack of open elements has a p element in scope,
                    then generate implied end tags, except for p elements. */
                    if($this->elementInScope('p')) {
                        $this->generateImpliedEndTags(array('p'));

                        /* If the current node is not a p element, then this is
                        a parse error. */
                        // k

                        /* If the stack of open elements has a p element in
                        scope, then pop elements from this stack until the stack
                        no longer has a p element in scope. */
                        for($n = count($this->stack) - 1; $n >= 0; $n--) {
                            if($this->elementInScope('p')) {
                                array_pop($this->stack);

                            } else {
                                break;
                            }
                        }
                    }
                break;

                /* An end tag whose tag name is "dd", "dt", or "li" */
                case 'dd': case 'dt': case 'li':
                    /* If the stack of open elements has an element in scope
                    whose tag name matches the tag name of the token, then
                    generate implied end tags, except for elements with the
                    same tag name as the token. */
                    if($this->elementInScope($token['name'])) {
                        $this->generateImpliedEndTags(array($token['name']));

                        /* If the current node is not an element with the same
                        tag name as the token, then this is a parse error. */
                        // w/e

                        /* If the stack of open elements has an element in scope
                        whose tag name matches the tag name of the token, then
                        pop elements from this stack until an element with that
                        tag name has been popped from the stack. */
                        for($n = count($this->stack) - 1; $n >= 0; $n--) {
                            if($this->stack[$n]->nodeName === $token['name']) {
                                $n = -1;
                            }

                            array_pop($this->stack);
                        }
                    }
                break;

                /* An end tag whose tag name is one of: "h1", "h2", "h3", "h4",
                "h5", "h6" */
                case 'h1': case 'h2': case 'h3': case 'h4': case 'h5': case 'h6':
                    $elements = array('h1', 'h2', 'h3', 'h4', 'h5', 'h6');

                    /* If the stack of open elements has in scope an element whose
                    tag name is one of "h1", "h2", "h3", "h4", "h5", or "h6", then
                    generate implied end tags. */
                    if($this->elementInScope($elements)) {
                        $this->generateImpliedEndTags();

                        /* Now, if the current node is not an element with the same
                        tag name as that of the token, then this is a parse error. */
                        // w/e

                        /* If the stack of open elements has in scope an element
                        whose tag name is one of "h1", "h2", "h3", "h4", "h5", or
                        "h6", then pop elements from the stack until an element
                        with one of those tag names has been popped from the stack. */
                        while($this->elementInScope($elements)) {
                            array_pop($this->stack);
                        }
                    }
                break;

                /* An end tag whose tag name is one of: "a", "b", "big", "em",
                "font", "i", "nobr", "s", "small", "strike", "strong", "tt", "u" */
                case 'a': case 'b': case 'big': case 'em': case 'font':
                case 'i': case 'nobr': case 's': case 'small': case 'strike':
                case 'strong': case 'tt': case 'u':
                    /* 1. Let the formatting element be the last element in
                    the list of active formatting elements that:
                        * is between the end of the list and the last scope
                        marker in the list, if any, or the start of the list
                        otherwise, and
                        * has the same tag name as the token.
                    */
                    while(true) {
                        for($a = count($this->a_formatting) - 1; $a >= 0; $a--) {
                            if($this->a_formatting[$a] === self::MARKER) {
                                break;

                            } elseif($this->a_formatting[$a]->tagName === $token['name']) {
                                $formatting_element = $this->a_formatting[$a];
                                $in_stack = in_array($formatting_element, $this->stack, true);
                                $fe_af_pos = $a;
                                break;
                            }
                        }

                        /* If there is no such node, or, if that node is
                        also in the stack of open elements but the element
                        is not in scope, then this is a parse error. Abort
                        these steps. The token is ignored. */
                        if(!isset($formatting_element) || ($in_stack &&
                        !$this->elementInScope($token['name']))) {
                            break;

                        /* Otherwise, if there is such a node, but that node
                        is not in the stack of open elements, then this is a
                        parse error; remove the element from the list, and
                        abort these steps. */
                        } elseif(isset($formatting_element) && !$in_stack) {
                            unset($this->a_formatting[$fe_af_pos]);
                            $this->a_formatting = array_merge($this->a_formatting);
                            break;
                        }

                        /* 2. Let the furthest block be the topmost node in the
                        stack of open elements that is lower in the stack
                        than the formatting element, and is not an element in
                        the phrasing or formatting categories. There might
                        not be one. */
                        $fe_s_pos = array_search($formatting_element, $this->stack, true);
                        $length = count($this->stack);

                        for($s = $fe_s_pos + 1; $s < $length; $s++) {
                            $category = $this->getElementCategory($this->stack[$s]->nodeName);

                            if($category !== self::PHRASING && $category !== self::FORMATTING) {
                                $furthest_block = $this->stack[$s];
                            }
                        }

                        /* 3. If there is no furthest block, then the UA must
                        skip the subsequent steps and instead just pop all
                        the nodes from the bottom of the stack of open
                        elements, from the current node up to the formatting
                        element, and remove the formatting element from the
                        list of active formatting elements. */
                        if(!isset($furthest_block)) {
                            for($n = $length - 1; $n >= $fe_s_pos; $n--) {
                                array_pop($this->stack);
                            }

                            unset($this->a_formatting[$fe_af_pos]);
                            $this->a_formatting = array_merge($this->a_formatting);
                            break;
                        }

                        /* 4. Let the common ancestor be the element
                        immediately above the formatting element in the stack
                        of open elements. */
                        $common_ancestor = $this->stack[$fe_s_pos - 1];

                        /* 5. If the furthest block has a parent node, then
                        remove the furthest block from its parent node. */
                        if($furthest_block->parentNode !== null) {
                            $furthest_block->parentNode->removeChild($furthest_block);
                        }

                        /* 6. Let a bookmark note the position of the
                        formatting element in the list of active formatting
                        elements relative to the elements on either side
                        of it in the list. */
                        $bookmark = $fe_af_pos;

                        /* 7. Let node and last node  be the furthest block.
                        Follow these steps: */
                        $node = $furthest_block;
                        $last_node = $furthest_block;

                        while(true) {
                            for($n = array_search($node, $this->stack, true) - 1; $n >= 0; $n--) {
                                /* 7.1 Let node be the element immediately
                                prior to node in the stack of open elements. */
                                $node = $this->stack[$n];

                                /* 7.2 If node is not in the list of active
                                formatting elements, then remove node from
                                the stack of open elements and then go back
                                to step 1. */
                                if(!in_array($node, $this->a_formatting, true)) {
                                    unset($this->stack[$n]);
                                    $this->stack = array_merge($this->stack);

                                } else {
                                    break;
                                }
                            }

                            /* 7.3 Otherwise, if node is the formatting
                            element, then go to the next step in the overall
                            algorithm. */
                            if($node === $formatting_element) {
                                break;

                            /* 7.4 Otherwise, if last node is the furthest
                            block, then move the aforementioned bookmark to
                            be immediately after the node in the list of
                            active formatting elements. */
                            } elseif($last_node === $furthest_block) {
                                $bookmark = array_search($node, $this->a_formatting, true) + 1;
                            }

                            /* 7.5 If node has any children, perform a
                            shallow clone of node, replace the entry for
