// 判斷是否為空
$wrong = $check->fn_empty('article', 'title, keyword, content');

// 判斷是否含有非法字符
$wrong = $check->fn_illegal_char('article', 'title, keyword, content');

if ($wrong) {
    foreach ($wrong as $key => $value) {
        $wrong_format .= $wrong[$key] . '<br>';
    }
    $dou->dou_msg($wrong_format, $_URL['article']);
}