php解析html类库simple_html_dom为常用的html分析类，解析器不仅仅只是帮助我们验证html文档；更能解析不符合W3C标准的html文档。它使用了类似jQuery的元素选择器，通过元素的id，class，tag等等来查找定位；同时还提供添加、删除、修改文档树的功能。当然，这样一款强大的html Dom解析器也不是尽善尽美；在使用的过程中我就遇到了如下错误。 程序报致命错误。 Fatal error: Maximum function nesting level of '256' reached, aborting! 也许作者也遇到了，但作者的环境可能与我的环境不同，作者在备注中有如下一句注释， * Found infinite loop in the case of broken html in restore_noise. Rewrote to protect from that. 仅管作者说明了这里可能会死循环，但我下者了的版本，依然遇到了死循环。或者致少超过了我的PHP的允许的递归次数。 下边附上完整的修改后的代码，修改后的代码仅仅是可用而已，并不完美，大家将就看下。 以下为 simple_html_dom.php 全文修改后的代码

size is the "real" number of bytes the dom was created from.
 *  but for most purposes, it's a really good estimation.
 * Paperg - Added the forceTagsClosed to the dom constructor.  Forcing tags closed is great for malformed html, but it CAN lead to parsing errors.
 * Allow the user to tell us how much they trust the html.
 * Paperg add the text and plaintext to the selectors for the find syntax.  plaintext implies text in the innertext of a node.  text implies that the tag is a text node.
 * This allows for us to find tags based on the text they contain.
 * Create find_ancestor_tag to see if a tag is - at any level - inside of another specific tag.
 * Paperg: added parse_charset so that we know about the character set of the source document.
 *  NOTE:  If the user's system has a routine called get_last_retrieve_url_contents_content_type availalbe, we will assume it's returning the content-type header from the
 *  last transfer or curl_exec, and we will parse that and use it in preference to any other method of charset detection.
 *
 * Found infinite loop in the case of broken html in restore_noise.  Rewrote to protect from that.
 * PaperG (John Schlick) Added get_display_size for "IMG" tags.
 *
 * Licensed under The MIT License
 * Redistributions of files must retain the above copyright notice.
 *
 * @author S.C. Chen 
 * @author John Schlick
 * @author Rus Carroll
 * @version 1.5 ($Rev: 196 $)
 * @package PlaceLocalInclude
 * @subpackage simple_html_dom
 */

/**
 * All of the Defines for the classes below.
 * @author S.C. Chen 
 */
define('HDOM_TYPE_ELEMENT', 1);
define('HDOM_TYPE_COMMENT', 2);
define('HDOM_TYPE_TEXT',    3);
define('HDOM_TYPE_ENDTAG',  4);
define('HDOM_TYPE_ROOT',    5);
define('HDOM_TYPE_UNKNOWN', 6);
define('HDOM_QUOTE_DOUBLE', 0);
define('HDOM_QUOTE_SINGLE', 1);
define('HDOM_QUOTE_NO',     3);
define('HDOM_INFO_BEGIN',   0);
define('HDOM_INFO_END',     1);
define('HDOM_INFO_QUOTE',   2);
define('HDOM_INFO_SPACE',   3);
define('HDOM_INFO_TEXT',    4);
define('HDOM_INFO_INNER',   5);
define('HDOM_INFO_OUTER',   6);
define('HDOM_INFO_ENDSPACE',7);
define('DEFAULT_TARGET_CHARSET', 'UTF-8');
define('DEFAULT_BR_TEXT', "\r\n");
define('DEFAULT_SPAN_TEXT', " ");
if (!defined('MAX_FILE_SIZE')) {
    define('MAX_FILE_SIZE', 600000);   
}
$makeup_levelval=0;
$restore_noiselevelval=0;
// helper functions
// -----------------------------------------------------------------------------
// get html dom from file
// $maxlen is defined in the code as PHP_STREAM_COPY_ALL which is defined as -1.
function file_get_html($url, $use_include_path = false, $context=null, $offset = -1, $maxLen=-1, $lowercase = true, $forceTagsClosed=true, $target_charset = DEFAULT_TARGET_CHARSET, $stripRN=true, $defaultBRText=DEFAULT_BR_TEXT, $defaultSpanText=DEFAULT_SPAN_TEXT)
{
    // We DO force the tags to be terminated.
    $dom = new simple_html_dom(null, $lowercase, $forceTagsClosed, $target_charset, $stripRN, $defaultBRText, $defaultSpanText);

   do {
      $repeat = false;
      if ($context!==NULL)
      {
         // Test if "Accept-Encoding: gzip" has been set in $context
         $params = stream_context_get_params($context);
         if (isset($params['options']['http']['header']) && preg_match('/gzip/', $params['options']['http']['header']) !== false)
         {
            $contents = file_get_contents('compress.zlib://'.$url, $use_include_path, $context, $offset);
         }
         else
         {
            $contents = file_get_contents($url, $use_include_path, $context, $offset);
         }
      }
      else
      {
         $contents = file_get_contents($url, $use_include_path, NULL, $offset);
      }

      // test if the URL doesn't return a 200 status
      if (isset($http_response_header) && strpos($http_response_header[0], '200') === false) {
         // has a 301 redirect header been sent?
         $pattern = "/^Location:\s*(.*)$/i";
         $location_headers = preg_grep($pattern, $http_response_header);

         if (!empty($location_headers) && preg_match($pattern, array_values($location_headers)[0], $matches)) {
            // set the URL to that returned via the redirect header and repeat this loop
            $url = $matches[1];
            $repeat = true;
         }
      }
   } while ($repeat);
    
   // stop processing if the header isn't a good responce
   if (isset($http_response_header) && strpos($http_response_header[0], '200') === false)
   {
      return false;
   }  
   
   // stop processing if the contents are too big
    if (empty($contents) || strlen($contents) > MAX_FILE_SIZE)
    {
        return false;
    }
    // The second parameter can force the selectors to all be lowercase.
    $dom->load($contents, $lowercase, $stripRN);
    return $dom;
}

// get html dom from string
function str_get_html($str, $lowercase=true, $forceTagsClosed=true, $target_charset = DEFAULT_TARGET_CHARSET, $stripRN=true, $defaultBRText=DEFAULT_BR_TEXT, $defaultSpanText=DEFAULT_SPAN_TEXT)
{
    $dom = new simple_html_dom(null, $lowercase, $forceTagsClosed, $target_charset, $stripRN, $defaultBRText, $defaultSpanText);
    if (empty($str) || strlen($str) > MAX_FILE_SIZE)
    {
        $dom->clear();
        return false;
    }
    $dom->load($str, $lowercase, $stripRN);
    return $dom;
}

// dump html dom tree
function dump_html_tree($node, $show_attr=true, $deep=0)
{
    $node->dump($node);
}


/**
 * simple html dom node
 * PaperG - added ability for "find" routine to lowercase the value of the selector.
 * PaperG - added $tag_start to track the start position of the tag in the total byte index
 *
 * @package PlaceLocalInclude
 */
class simple_html_dom_node
{
    public $nodetype = HDOM_TYPE_TEXT;
    public $tag = 'text';
    public $attr = array();
    public $children = array();
    public $nodes = array();
    public $parent = null;
    // The "info" array - see HDOM_INFO_... for what each element contains.
    public $_ = array();
    public $tag_start = 0;
    private $dom = null;

    function __construct($dom)
    {
        $this->dom = $dom;
        $dom->nodes[] = $this;
    }

//    function __destruct()//此析构涵数在某种状态下会导至死循环，原因不明。暂时直接注释掉
//    {
////        $this->clear();
//    }

    function __toString()
    {
        return $this->outertext();
    }

    // clean up memory due to php5 circular references memory leak...
    function clear()
    {
        $this->dom = null;
        $this->nodes = null;
        $this->parent = null;
        $this->children = null;
    }

    // dump node's tree
    function dump($show_attr=true, $deep=0)
    {
        $lead = str_repeat('    ', $deep);

        echo $lead.$this->tag;
        if ($show_attr && count($this->attr)>0)
        {
            echo '(';
            foreach ($this->attr as $k=>$v)
                echo "[$k]=>\"".$this->$k.'", ';
            echo ')';
        }
        echo "\n";

        if ($this->nodes)
        {
            foreach ($this->nodes as $c)
            {
                $c->dump($show_attr, $deep+1);
            }
        }
    }


    // Debugging function to dump a single dom node with a bunch of information about it.
    function dump_node($echo=true)
    {

        $string = $this->tag;
        if (count($this->attr)>0)
        {
            $string .= '(';
            foreach ($this->attr as $k=>$v)
            {
                $string .= "[$k]=>\"".$this->$k.'", ';
            }
            $string .= ')';
        }
        if (count($this->_)>0)
        {
            $string .= ' $_ (';
            foreach ($this->_ as $k=>$v)
            {
                if (is_array($v))
                {
                    $string .= "[$k]=>(";
                    foreach ($v as $k2=>$v2)
                    {
                        $string .= "[$k2]=>\"".$v2.'", ';
                    }
                    $string .= ")";
                } else {
                    $string .= "[$k]=>\"".$v.'", ';
                }
            }
            $string .= ")";
        }

        if (isset($this->text))
        {
            $string .= " text: (" . $this->text . ")";
        }

        $string .= " HDOM_INNER_INFO: '";
        if (isset($node->_[HDOM_INFO_INNER]))
        {
            $string .= $node->_[HDOM_INFO_INNER] . "'";
        }
        else
        {
            $string .= ' NULL ';
        }

        $string .= " children: " . count($this->children);
        $string .= " nodes: " . count($this->nodes);
        $string .= " tag_start: " . $this->tag_start;
        $string .= "\n";

        if ($echo)
        {
            echo $string;
            return;
        }
        else
        {
            return $string;
        }
    }

    // returns the parent of node
    // If a node is passed in, it will reset the parent of the current node to that one.
    function parent($parent=null)
    {
        // I am SURE that this doesn't work properly.
        // It fails to unset the current node from it's current parents nodes or children list first.
        if ($parent !== null)
        {
            $this->parent = $parent;
            $this->parent->nodes[] = $this;
            $this->parent->children[] = $this;
        }

        return $this->parent;
    }

    // verify that node has children
    function has_child()
    {
        return !empty($this->children);
    }

    // returns children of node
    function children($idx=-1)
    {
        if ($idx===-1)
        {
            return $this->children;
        }
        if (isset($this->children[$idx])) return $this->children[$idx];
        return null;
    }

    // returns the first child of node
    function first_child()
    {
        if (count($this->children)>0)
        {
            return $this->children[0];
        }
        return null;
    }

    // returns the last child of node
    function last_child()
    {
        if (($count=count($this->children))>0)
        {
            return $this->children[$count-1];
        }
        return null;
    }

    // returns the next sibling of node
    function next_sibling()
    {
        if ($this->parent===null)
        {
            return null;
        }

        $idx = 0;
        $count = count($this->parent->children);
        while ($idx<$count && $this!==$this->parent->children[$idx])
        {
            ++$idx;
        }
        if (++$idx>=$count)
        {
            return null;
        }
        return $this->parent->children[$idx];
    }

    // returns the previous sibling of node
    function prev_sibling()
    {
        if ($this->parent===null) return null;
        $idx = 0;
        $count = count($this->parent->children);
        while ($idx<$count && $this!==$this->parent->children[$idx])
            ++$idx;
        if (--$idx<0) return null;
        return $this->parent->children[$idx];
    }

    // function to locate a specific ancestor tag in the path to the root.
    function find_ancestor_tag($tag)
    {
        global $debugObject;
        if (is_object($debugObject)) { $debugObject->debugLogEntry(1); }

        // Start by including ourselves in the comparison.
        $returnDom = $this;

        while (!is_null($returnDom))
        {
            if (is_object($debugObject)) { $debugObject->debugLog(2, "Current tag is: " . $returnDom->tag); }

            if ($returnDom->tag == $tag)
            {
                break;
            }
            $returnDom = $returnDom->parent;
        }
        return $returnDom;
    }

    // get dom node's inner html
    function innertext()
    {
        global $restore_noiselevelval;


        if (isset($this->_[HDOM_INFO_INNER])) return $this->_[HDOM_INFO_INNER];
        if (isset($this->_[HDOM_INFO_TEXT])){
            $tttaaaa= $this->dom->restore_noise($this->_[HDOM_INFO_TEXT]);
            $restore_noiselevelval--;
            return $tttaaaa;
        }

        $ret = '';
        foreach ($this->nodes as $n)
            $ret .= $n->outertext();
        return $ret;
    }

    // get dom node's outer text (with tag)
    function outertext($levelval=0)
    {
        $levelval+=1;
        if($levelval==200){//递归调用200次时，就直接终止取空并返回
            return '';
        }
        global $restore_noiselevelval;
        global $debugObject;
        if (is_object($debugObject))
        {
            $text = '';
            if ($this->tag == 'text')
            {
                if (!empty($this->text))
                {
                    $text = " with text: " . $this->text;
                }
            }
            $debugObject->debugLog(1, 'Innertext of tag: ' . $this->tag . $text);
        }

        if ($this->tag==='root') return $this->innertext();

        // trigger callback
        if ($this->dom && $this->dom->callback!==null)
        {
            call_user_func_array($this->dom->callback, array($this));
        }

        if (isset($this->_[HDOM_INFO_OUTER])) return $this->_[HDOM_INFO_OUTER];
        if (isset($this->_[HDOM_INFO_TEXT])) {
            $tttaaaa= $this->dom->restore_noise($this->_[HDOM_INFO_TEXT]);
            $restore_noiselevelval--;
            return $tttaaaa;
        }

        // render begin tag
        if ($this->dom && $this->dom->nodes[$this->_[HDOM_INFO_BEGIN]])
        {   global $makeup_levelval;
//            echo $makeup_levelval,'====';
            if($makeup_levelval>200){
                $ret = "";
            }else{
                $ret = $this->dom->nodes[$this->_[HDOM_INFO_BEGIN]]->makeup();
                $makeup_levelval--;
            }


        } else {
            $ret = "";
        }

        // render inner text
        if (isset($this->_[HDOM_INFO_INNER]))
        {
            // If it's a br tag...  don't return the HDOM_INNER_INFO that we may or may not have added.
            if ($this->tag != "br")
            {
                $ret .= $this->_[HDOM_INFO_INNER];
            }
        } else {
            if ($this->nodes)
            {
                foreach ($this->nodes as $n)
                {
                    $ret .= $this->convert_text($n->outertext($levelval));
                }
            }
        }

        // render end tag
        if (isset($this->_[HDOM_INFO_END]) && $this->_[HDOM_INFO_END]!=0)
            $ret .= 'tag.'>';
        return $ret;
    }

    // get dom node's plain text
    function text($levelval=0 )
    {

        $levelval+=1;
        if($levelval==200){//递归调用200次时，就直接终止取空并返回
            return '';
        }
        global $restore_noiselevelval;


        if (isset($this->_[HDOM_INFO_INNER])) return $this->_[HDOM_INFO_INNER];
        switch ($this->nodetype)
        {
            case HDOM_TYPE_TEXT:

                $tttaaaa= $this->dom->restore_noise($this->_[HDOM_INFO_TEXT]);
                $restore_noiselevelval--;
                return $tttaaaa;

            case HDOM_TYPE_COMMENT: return '';
            case HDOM_TYPE_UNKNOWN: return '';
        }
        if (strcasecmp($this->tag, 'script')===0) return '';
        if (strcasecmp($this->tag, 'style')===0) return '';

        $ret = '';
        // In rare cases, (always node type 1 or HDOM_TYPE_ELEMENT - observed for some span tags, and some p tags) $this->nodes is set to NULL.
        // NOTE: This indicates that there is a problem where it's set to NULL without a clear happening.
        // WHY is this happening?
        if (!is_null($this->nodes))
        {
            foreach ($this->nodes as $n)
            {
                $ret .= $this->convert_text($n->text($levelval));
            }

            // If this node is a span... add a space at the end of it so multiple spans don't run into each other.  This is plaintext after all.
            if ($this->tag == "span")
            {
                $ret .= $this->dom->default_span_text;
            }


        }
        return $ret;
    }

    function xmltext()
    {
        $ret = $this->innertext();
        $ret = str_ireplace('', '', $ret);
        return $ret;
    }

    // build node's text with tag
    function makeup()
    {
        global $makeup_levelval;
        $makeup_levelval++;

        // text, comment, unknown
        global $restore_noiselevelval;
        if (isset($this->_[HDOM_INFO_TEXT])){

            $tttaaaa= $this->dom->restore_noise($this->_[HDOM_INFO_TEXT]);
            $restore_noiselevelval--;
            return $tttaaaa;

        }

        $ret = '<'.$this->tag;
        $i = -1;

        foreach ($this->attr as $key=>$val)
        {
            ++$i;

            // skip removed attribute
            if ($val===null || $val===false)
                continue;

            $ret .= $this->_[HDOM_INFO_SPACE][$i][0];
            //no value attr: nowrap, checked selected...
            if ($val===true)
                $ret .= $key;
            else {
                switch ($this->_[HDOM_INFO_QUOTE][$i])
                {
                    case HDOM_QUOTE_DOUBLE: $quote = '"'; break;
                    case HDOM_QUOTE_SINGLE: $quote = '\''; break;
                    default: $quote = '';
                }
                $ret .= $key.$this->_[HDOM_INFO_SPACE][$i][1].'='.$this->_[HDOM_INFO_SPACE][$i][2].$quote.$val.$quote;
            }
        }
//        if($restore_noiselevelval>200){//递归调用200次时，就直接终止取空并返回
//        }else{
//            $ret = $this->dom->restore_noise($ret);
//        }
        $ret = $this->dom->restore_noise($ret);
        return $ret . $this->_[HDOM_INFO_ENDSPACE] . '>';
    }

    // find elements by css selector
    //PaperG - added ability for find to lowercase the value of the selector.
    function find($selector, $idx=null, $lowercase=false)
    {
        $selectors = $this->parse_selector($selector);
        if (($count=count($selectors))===0) return array();
        $found_keys = array();

        // find each selector
        for ($c=0; $c<$count; ++$c)
        {
            // The change on the below line was documented on the sourceforge code tracker id 2788009
            // used to be: if (($levle=count($selectors[0]))===0) return array();
            if (($levle=count($selectors[$c]))===0) return array();
            if (!isset($this->_[HDOM_INFO_BEGIN])) return array();

            $head = array($this->_[HDOM_INFO_BEGIN]=>1);

            // handle descendant selectors, no recursive!
            for ($l=0; $l<$levle; ++$l)
            {
                $ret = array();
                foreach ($head as $k=>$v)
                {
                    $n = ($k===-1) ? $this->dom->root : $this->dom->nodes[$k];
                    //PaperG - Pass this optional parameter on to the seek function.
                    $n->seek($selectors[$c][$l], $ret, $lowercase);
                }
                $head = $ret;
            }

            foreach ($head as $k=>$v)
            {
                if (!isset($found_keys[$k]))
                    $found_keys[$k] = 1;
            }
        }

        // sort keys
        ksort($found_keys);

        $found = array();
        foreach ($found_keys as $k=>$v)
            $found[] = $this->dom->nodes[$k];

        // return nth-element or array
        if (is_null($idx)) return $found;
        else if ($idx<0) $idx = count($found) + $idx;
        return (isset($found[$idx])) ? $found[$idx] : null;
    }

    // seek for given conditions
    // PaperG - added parameter to allow for case insensitive testing of the value of a selector.
    protected function seek($selector, &$ret, $lowercase=false)
    {
        global $debugObject;
        if (is_object($debugObject)) { $debugObject->debugLogEntry(1); }

        list($tag, $key, $val, $exp, $no_key) = $selector;

        // xpath index
        if ($tag && $key && is_numeric($key))
        {
            $count = 0;
            foreach ($this->children as $c)
            {
                if ($tag==='*' || $tag===$c->tag) {
                    if (++$count==$key) {
                        $ret[$c->_[HDOM_INFO_BEGIN]] = 1;
                        return;
                    }
                }
            }
            return;
        }

        $end = (!empty($this->_[HDOM_INFO_END])) ? $this->_[HDOM_INFO_END] : 0;
        if ($end==0) {
            $parent = $this->parent;
            while (!isset($parent->_[HDOM_INFO_END]) && $parent!==null) {
                $end -= 1;
                $parent = $parent->parent;
            }
            $end += $parent->_[HDOM_INFO_END];
        }

        for ($i=$this->_[HDOM_INFO_BEGIN]+1; $i<$end; ++$i) {
            $node = $this->dom->nodes[$i];

            $pass = true;

            if ($tag==='*' && !$key) {
                if (in_array($node, $this->children, true))
                    $ret[$i] = 1;
                continue;
            }

            // compare tag
            if ($tag && $tag!=$node->tag && $tag!=='*') {$pass=false;}
            // compare key
            if ($pass && $key) {
                if ($no_key) {
                    if (isset($node->attr[$key])) $pass=false;
                } else {
                    if (($key != "plaintext") && !isset($node->attr[$key])) $pass=false;
                }
            }
            // compare value
            if ($pass && $key && $val  && $val!=='*') {
                // If they have told us that this is a "plaintext" search then we want the plaintext of the node - right?
                if ($key == "plaintext") {
                    // $node->plaintext actually returns $node->text();
                    $nodeKeyValue = $node->text();
                } else {
                    // this is a normal search, we want the value of that attribute of the tag.
                    $nodeKeyValue = $node->attr[$key];
                }
                if (is_object($debugObject)) {$debugObject->debugLog(2, "testing node: " . $node->tag . " for attribute: " . $key . $exp . $val . " where nodes value is: " . $nodeKeyValue);}

                //PaperG - If lowercase is set, do a case insensitive test of the value of the selector.
                if ($lowercase) {
                    $check = $this->match($exp, strtolower($val), strtolower($nodeKeyValue));
                } else {
                    $check = $this->match($exp, $val, $nodeKeyValue);
                }
                if (is_object($debugObject)) {$debugObject->debugLog(2, "after match: " . ($check ? "true" : "false"));}

                // handle multiple class
                if (!$check && strcasecmp($key, 'class')===0) {
                    foreach (explode(' ',$node->attr[$key]) as $k) {
                        // Without this, there were cases where leading, trailing, or double spaces lead to our comparing blanks - bad form.
                        if (!empty($k)) {
                            if ($lowercase) {
                                $check = $this->match($exp, strtolower($val), strtolower($k));
                            } else {
                                $check = $this->match($exp, $val, $k);
                            }
                            if ($check) break;
                        }
                    }
                }
                if (!$check) $pass = false;
            }
            if ($pass) $ret[$i] = 1;
            unset($node);
        }
        // It's passed by reference so this is actually what this function returns.
        if (is_object($debugObject)) {$debugObject->debugLog(1, "EXIT - ret: ", $ret);}
    }

    protected function match($exp, $pattern, $value) {
        global $debugObject;
        if (is_object($debugObject)) {$debugObject->debugLogEntry(1);}

        switch ($exp) {
            case '=':
                return ($value===$pattern);
            case '!=':
                return ($value!==$pattern);
            case '^=':
                return preg_match("/^".preg_quote($pattern,'/')."/", $value);
            case '$=':
                return preg_match("/".preg_quote($pattern,'/')."$/", $value);
            case '*=':
                if ($pattern[0]=='/') {
                    return preg_match($pattern, $value);
                }
                return preg_match("/".$pattern."/i", $value);
        }
        return false;
    }

    protected function parse_selector($selector_string) {
        global $debugObject;
        if (is_object($debugObject)) {$debugObject->debugLogEntry(1);}

        // pattern of CSS selectors, modified from mootools
        // Paperg: Add the colon to the attrbute, so that it properly finds  like google does.
        // Note: if you try to look at this attribute, yo MUST use getAttribute since $dom->x:y will fail the php syntax check.
// Notice the \[ starting the attbute?  and the @? following?  This implies that an attribute can begin with an @ sign that is not captured.
// This implies that an html attribute specifier may start with an @ sign that is NOT captured by the expression.
// farther study is required to determine of this should be documented or removed.
//        $pattern = "/([\w-:\*]*)(?:\#([\w-]+)|\.([\w-]+))?(?:\[@?(!?[\w-]+)(?:([!*^$]?=)[\"']?(.*?)[\"']?)?\])?([\/, ]+)/is";
        $pattern = "/([\w\-:\*]*)(?:\#([\w\-]+)|\.([\w\-]+))?(?:\[@?(!?[\w\-:]+)(?:([!*^$]?=)[\"']?(.*?)[\"']?)?\])?([\/, ]+)/is";
        preg_match_all($pattern, trim($selector_string).' ', $matches, PREG_SET_ORDER);
        if (is_object($debugObject)) {$debugObject->debugLog(2, "Matches Array: ", $matches);}

        $selectors = array();
        $result = array();
        //print_r($matches);

        foreach ($matches as $m) {
            $m[0] = trim($m[0]);
            if ($m[0]==='' || $m[0]==='/' || $m[0]==='//') continue;
            // for browser generated xpath
            if ($m[1]==='tbody') continue;

            list($tag, $key, $val, $exp, $no_key) = array($m[1], null, null, '=', false);
            if (!empty($m[2])) {$key='id'; $val=$m[2];}
            if (!empty($m[3])) {$key='class'; $val=$m[3];}
            if (!empty($m[4])) {$key=$m[4];}
            if (!empty($m[5])) {$exp=$m[5];}
            if (!empty($m[6])) {$val=$m[6];}

            // convert to lowercase
            if ($this->dom->lowercase) {$tag=strtolower($tag); $key=strtolower($key);}
            //elements that do NOT have the specified attribute
            if (isset($key[0]) && $key[0]==='!') {$key=substr($key, 1); $no_key=true;}

            $result[] = array($tag, $key, $val, $exp, $no_key);
            if (trim($m[7])===',') {
                $selectors[] = $result;
                $result = array();
            }
        }
        if (count($result)>0)
            $selectors[] = $result;
        return $selectors;
    }

    function __get($name) {
        if (isset($this->attr[$name]))
        {
            return $this->convert_text($this->attr[$name]);
        }
        switch ($name) {
            case 'outertext': return $this->outertext();
            case 'innertext': return $this->innertext();
            case 'plaintext': return $this->text();
            case 'xmltext': return $this->xmltext();
            default: return array_key_exists($name, $this->attr);
        }
    }

    function __set($name, $value) {
        switch ($name) {
            case 'outertext': return $this->_[HDOM_INFO_OUTER] = $value;
            case 'innertext':
                if (isset($this->_[HDOM_INFO_TEXT])) return $this->_[HDOM_INFO_TEXT] = $value;
                return $this->_[HDOM_INFO_INNER] = $value;
        }
        if (!isset($this->attr[$name])) {
            $this->_[HDOM_INFO_SPACE][] = array(' ', '', '');
            $this->_[HDOM_INFO_QUOTE][] = HDOM_QUOTE_DOUBLE;
        }
        $this->attr[$name] = $value;
    }

    function __isset($name) {
        switch ($name) {
            case 'outertext': return true;
            case 'innertext': return true;
            case 'plaintext': return true;
        }
        //no value attr: nowrap, checked selected...
        return (array_key_exists($name, $this->attr)) ? true : isset($this->attr[$name]);
    }

    function __unset($name) {
        if (isset($this->attr[$name]))
            unset($this->attr[$name]);
    }

    // PaperG - Function to convert the text from one character set to another if the two sets are not the same.
    function convert_text($text)
    {
        global $debugObject;
        if (is_object($debugObject)) {$debugObject->debugLogEntry(1);}

        $converted_text = $text;

        $sourceCharset = "";
        $targetCharset = "";

        if ($this->dom)
        {
            $sourceCharset = strtoupper($this->dom->_charset);
            $targetCharset = strtoupper($this->dom->_target_charset);
        }
        if (is_object($debugObject)) {$debugObject->debugLog(3, "source charset: " . $sourceCharset . " target charaset: " . $targetCharset);}

        if (!empty($sourceCharset) && !empty($targetCharset) && (strcasecmp($sourceCharset, $targetCharset) != 0))
        {
            // Check if the reported encoding could have been incorrect and the text is actually already UTF-8
            if ((strcasecmp($targetCharset, 'UTF-8') == 0) && ($this->is_utf8($text)))
            {
                $converted_text = $text;
            }
            else
            {
                $converted_text = iconv($sourceCharset, $targetCharset, $text);
            }
        }

        // Lets make sure that we don't have that silly BOM issue with any of the utf-8 text we output.
        if ($targetCharset == 'UTF-8')
        {
            if (substr($converted_text, 0, 3) == "\xef\xbb\xbf")
            {
                $converted_text = substr($converted_text, 3);
            }
            if (substr($converted_text, -3) == "\xef\xbb\xbf")
            {
                $converted_text = substr($converted_text, 0, -3);
            }
        }

        return $converted_text;
    }

    /**
    * Returns true if $string is valid UTF-8 and false otherwise.
    *
    * @param mixed $str String to be tested
    * @return boolean
    */
    static function is_utf8($str)
    {
        $c=0; $b=0;
        $bits=0;
        $len=strlen($str);
        for($i=0; $i<$len; $i++)
        {
            $c=ord($str[$i]);
            if($c > 128)
            {
                if(($c >= 254)) return false;
                elseif($c >= 252) $bits=6;
                elseif($c >= 248) $bits=5;
                elseif($c >= 240) $bits=4;
                elseif($c >= 224) $bits=3;
                elseif($c >= 192) $bits=2;
                else return false;
                if(($i+$bits) > $len) return false;
                while($bits > 1)
                {
                    $i++;
                    $b=ord($str[$i]);
                    if($b < 128 || $b > 191) return false;
                    $bits--;
                }
            }
        }
        return true;
    }
    /*
    function is_utf8($string)
    {
        //this is buggy
        return (utf8_encode(utf8_decode($string)) == $string);
    }
    */

    /**
     * Function to try a few tricks to determine the displayed size of an img on the page.
     * NOTE: This will ONLY work on an IMG tag. Returns FALSE on all other tag types.
     *
     * @author John Schlick
     * @version April 19 2012
     * @return array an array containing the 'height' and 'width' of the image on the page or -1 if we can't figure it out.
     */
    function get_display_size()
    {
        global $debugObject;

        $width = -1;
        $height = -1;

        if ($this->tag !== 'img')
        {
            return false;
        }

        // See if there is aheight or width attribute in the tag itself.
        if (isset($this->attr['width']))
        {
            $width = $this->attr['width'];
        }

        if (isset($this->attr['height']))
        {
            $height = $this->attr['height'];
        }

        // Now look for an inline style.
        if (isset($this->attr['style']))
        {
            // Thanks to user gnarf from stackoverflow for this regular expression.
            $attributes = array();
            preg_match_all("/([\w\-]+)\s*:\s*([^;]+)\s*;?/", $this->attr['style'], $matches, PREG_SET_ORDER);
            foreach ($matches as $match) {
              $attributes[$match[1]] = $match[2];
            }

            // If there is a width in the style attributes:
            if (isset($attributes['width']) && $width == -1)
            {
                // check that the last two characters are px (pixels)
                if (strtolower(substr($attributes['width'], -2)) == 'px')
                {
                    $proposed_width = substr($attributes['width'], 0, -2);
                    // Now make sure that it's an integer and not something stupid.
                    if (filter_var($proposed_width, FILTER_VALIDATE_INT))
                    {
                        $width = $proposed_width;
                    }
                }
            }

            // If there is a width in the style attributes:
            if (isset($attributes['height']) && $height == -1)
            {
                // check that the last two characters are px (pixels)
                if (strtolower(substr($attributes['height'], -2)) == 'px')
                {
                    $proposed_height = substr($attributes['height'], 0, -2);
                    // Now make sure that it's an integer and not something stupid.
                    if (filter_var($proposed_height, FILTER_VALIDATE_INT))
                    {
                        $height = $proposed_height;
                    }
                }
            }

        }

        // Future enhancement:
        // Look in the tag to see if there is a class or id specified that has a height or width attribute to it.

        // Far future enhancement
        // Look at all the parent tags of this image to see if they specify a class or id that has an img selector that specifies a height or width
        // Note that in this case, the class or id will have the img subselector for it to apply to the image.

        // ridiculously far future development
        // If the class or id is specified in a SEPARATE css file thats not on the page, go get it and do what we were just doing for the ones on the page.

        $result = array('height' => $height,
                        'width' => $width);
        return $result;
    }

    // camel naming conventions
    function getAllAttributes() {return $this->attr;}
    function getAttribute($name) {return $this->__get($name);}
    function setAttribute($name, $value) {$this->__set($name, $value);}
    function hasAttribute($name) {return $this->__isset($name);}
    function removeAttribute($name) {$this->__set($name, null);}
    function getElementById($id) {return $this->find("#$id", 0);}
    function getElementsById($id, $idx=null) {return $this->find("#$id", $idx);}
    function getElementByTagName($name) {return $this->find($name, 0);}
    function getElementsByTagName($name, $idx=null) {return $this->find($name, $idx);}
    function parentNode() {return $this->parent();}
    function childNodes($idx=-1) {return $this->children($idx);}
    function firstChild() {return $this->first_child();}
    function lastChild() {return $this->last_child();}
    function nextSibling() {return $this->next_sibling();}
    function previousSibling() {return $this->prev_sibling();}
    function hasChildNodes() {return $this->has_child();}
    function nodeName() {return $this->tag;}
    function appendChild($node) {$node->parent($this); return $node;}

}

/**
 * simple html dom parser
 * Paperg - in the find routine: allow us to specify that we want case insensitive testing of the value of the selector.
 * Paperg - change $size from protected to public so we can easily access it
 * Paperg - added ForceTagsClosed in the constructor which tells us whether we trust the html or not.  Default is to NOT trust it.
 *
 * @package PlaceLocalInclude
 */
class simple_html_dom
{
    public $root = null;
    public $nodes = array();
    public $callback = null;
    public $lowercase = false;
    // Used to keep track of how large the text was when we started.
    public $original_size;
    public $size;
    protected $pos;
    protected $doc;
    protected $char;
    protected $cursor;
    protected $parent;
    protected $noise = array();
    protected $token_blank = " \t\r\n";
    protected $token_equal = ' =/>';
    protected $token_slash = " />\r\n\t";
    protected $token_attr = ' >';
    // Note that this is referenced by a child node, and so it needs to be public for that node to see this information.
    public $_charset = '';
    public $_target_charset = '';
    protected $default_br_text = "";
    public $default_span_text = "";

    // use isset instead of in_array, performance boost about 30%...
    protected $self_closing_tags = array('img'=>1, 'br'=>1, 'input'=>1, 'meta'=>1, 'link'=>1, 'hr'=>1, 'base'=>1, 'embed'=>1, 'spacer'=>1);
    protected $block_tags = array('root'=>1, 'body'=>1, 'form'=>1, 'div'=>1, 'span'=>1, 'table'=>1);
    // Known sourceforge issue #2977341
    // B tags that are not closed cause us to return everything to the end of the document.
    protected $optional_closing_tags = array(
        'tr'=>array('tr'=>1, 'td'=>1, 'th'=>1),
        'th'=>array('th'=>1),
        'td'=>array('td'=>1),
        'li'=>array('li'=>1),
        'dt'=>array('dt'=>1, 'dd'=>1),
        'dd'=>array('dd'=>1, 'dt'=>1),
        'dl'=>array('dd'=>1, 'dt'=>1),
        'p'=>array('p'=>1),
        'nobr'=>array('nobr'=>1),
        'b'=>array('b'=>1),
      'option'=>array('option'=>1),
    );

    function __construct($str=null, $lowercase=true, $forceTagsClosed=true, $target_charset=DEFAULT_TARGET_CHARSET, $stripRN=true, $defaultBRText=DEFAULT_BR_TEXT, $defaultSpanText=DEFAULT_SPAN_TEXT)
    {
        if ($str)
        {
            if (preg_match("/^http:\/\//i",$str) || is_file($str))
            {
                $this->load_file($str);
            }
            else
            {
                $this->load($str, $lowercase, $stripRN, $defaultBRText, $defaultSpanText);
            }
        }
        // Forcing tags to be closed implies that we don't trust the html, but it can lead to parsing errors if we SHOULD trust the html.
        if (!$forceTagsClosed) {
            $this->optional_closing_array=array();
        }
        $this->_target_charset = $target_charset;
    }

    function __destruct()
    {
        $this->clear();
    }

    // load html from string
    function load($str, $lowercase=true, $stripRN=true, $defaultBRText=DEFAULT_BR_TEXT, $defaultSpanText=DEFAULT_SPAN_TEXT)
    {
        global $debugObject;

        // prepare
        $this->prepare($str, $lowercase, $stripRN, $defaultBRText, $defaultSpanText);
        // strip out comments
        $this->remove_noise("''is");
        // strip out cdata
        $this->remove_noise("''is", true);
        // Per sourceforge http://sourceforge.net/tracker/?func=detail&aid=2949097&group_id=218559&atid=1044037
        // Script tags removal now preceeds style tag removal.
        // strip out