iframe里面表单提交后如何跳出iframe重定向到另一个页面

if (isset($_POST['orderNo'])) {
    if (!empty($_POST['remark'])) {
        $form = "<form action="{$_POST['remark']}" method="post" target="_top" id="resultForm">";

        foreach ($_POST as $key => $val) {
            $form .= "<input name="{$key}" type="hidden" value="{$val}" />";
        }

        $form .= "</form>";

        echo $form;
echo <<<SCRIPT
<script>
window.onload =function() {
    document.getElementById('resultForm').submit();
}
</script>
SCRIPT;

　　form元素target属性给_top值