PHP表单验证到一个简单的div

Question

我可以使用PHP表单配置错误div。 我想有一个简单的div显示表格下面的错误。

这是我的代码：

PHP

<?php 
if (isset($_REQUEST['submitted'])) {
    $errors = array();
    if (!empty($_REQUEST['firstname'])) {
        $firstname = $_REQUEST['firstname'];
        $pattern = "/^[a-zA-Z0-9\_]{2,20}/";
        if (preg_match($pattern,$firstname)){ 
            $firstname = $_REQUEST['firstname'];
        } else { 
            $errors[] = 'Your Name can only contain _, 1-9, A-Z or a-z 2-20 long.';
        }
    } else {
        $errors[] = 'You forgot to enter your First Name.';
    }
}

if (isset($_REQUEST['submitted'])) {
if (empty($errors)) { 
    $from = "From";
    $to = "mail@mail.com"; 
    $subject = "test" . $name . "";

    $message = "Message from " . $firstname . " 

    mail($to,$subject,$message,$from);
    header('Location: http://www.google.com');
  }
}
?>

HTML

<form method="post" action="contactform.php">
    <div class="field">
        <label for="firstname">First Name</label>
        <input type="text" name="firstname" id="firstname" />

    </div>

    <ul class="actions">
        <li>
            <input type="submit" input name="submitted" value="Send Message" />
        </li>
    </ul>
</form>

非常感谢！