php strip_tags延伸函数-处理html（采集用的上）

/**
 * This function turns HTML into text
 * 将html转化为txt 
 */
function html2txt($document) {
    $search = array ('@<script[^>]*?>.*?</script>@si', // Strip out javascript
                    '@<style[^>]*?>.*?</style>@siU', // Strip style tags properly
                    '@<[\\/\\!]*?[^<>]*?>@si', // Strip out HTML tags
                    '@<![\\s\\S]*?--[ \\t\\n\\r]*>@' )// Strip multi-line comments including CDATA
    ;
    $text = preg_replace ( $search, '', $document );
    return $text;
}

/**
 * removes the HTML tags along with their contents
 * 移除/过滤html标签并且移除标签内的内容
 * 注:$tags为需要保留的标签  invert为true时结果相反
 */
function strip_tags_content($text, $tags = '', $invert = FALSE) {
    preg_match_all ( '/<(.+?)[\\s]*\\/?[\\s]*>/si', trim ( $tags ), $tags );
    $tags = array_unique ( $tags [1] );

    if (is_array ( $tags ) and count ( $tags ) > 0) {
        if ($invert == FALSE) {
            return preg_replace ( '@<(?!(?:' . implode ( '|', $tags ) . ')\\b)(\\w+)\\b.*?>.*?</\\1>@si', '', $text );
        } else {
            return preg_replace ( '@<(' . implode ( '|', $tags ) . ')\\b.*?>.*?</\\1>@si', '', $text );
        }
    } elseif ($invert == FALSE) {
        return preg_replace ( '@<(\\w+)\\b.*?>.*?</\\1>@si', '', $text );
    }
    return $text;
}
//该片段来自于http://outofmemory.cn