Extensible search highlighting in PHP

Based on Dean's original Google Hilite, but refactored a bit to make it easy to add support for more search engines (currently supports some 20-odd major searches).

)([^<]+)?(\b'.$term.'\b)/i', $text)) {
        $matched = "Spoon!";
      } else {
        $mismatched = "Whoops";
      }
      if (!preg_match('/<.+>/',$text)) {
        $text = preg_replace('/(\b'.$term.'\b)/i','$1',$text);  
      } else {
        $text = preg_replace('/(?<=>)([^<]+)?(\b'.$term.'\b)/i','$1$2',$text);
      }
    }
    $query_terms = implode(" ", $query_array);
    $query_terms = htmlspecialchars(urldecode($query_terms));
    //If all terms matched, just tell them you did the highlighting.
    if($matched) {
      //Change this message if you like.
      $message = "
It seems you arrived at this page from a search engine.  To help you find "
        . "what you were looking for, your search terms (\"$query_terms\") should "
        . "be highlighted with yellow backgrounds, like this.
";
      $text = $message . $text;
    } elseif($mismatched) {
      //If only some or no terms matched, offer to repeat the search locally.
      $query = implode("+", $query_array);                      
      //Also change this message if you like.                   
      $message = "
It seems you arrived at this page from a search engine, but that some "
        . "or all of the terms you searched for (\"$query_terms\") aren’t in this page.  Would you like to "
        . "try your search again using this site’s built-in search?  It might be more accurate.
";
      if($matched) {
        $message .= "
Any of your search terms which do appear in this page "
          . "should be highlighted with yellow backgrounds, like this.
";
      }
      $text = $message . $text;
    }
  }
  return $text;
}
?>