PHP 过滤HTML中除img以外的标签

/*过滤html标签*/  
    public function cleanhtml($str,$tags='<img><a>'){//过滤时默认保留html中的<a><img>标签  
        $search = array(  
                        '@<script[^>]*?>.*?</script>@si',  // Strip out javascript  
/*                      '@<[\/\!]*?[^<>]*?>@si',            // Strip out HTML tags*/  
                        '@<style[^>]*?>.*?</style>@siU',    // Strip style tags properly   
                        '@<![\s\S]*?--[ \t\n\r]*>@'         // Strip multi-line comments including CDATA   
        );   
        $str = preg_replace($search, '', $str);  
        $str = strip_tags($str,$tags);  
        return $str;  
    }