PHP Contact Form validation on submit - php

Question

So the deal is this: the validation process starts after the user hits submit. However for some reason the code is not working.
PHP:
if ($_POST['submitted']) {
if(!filter_var($email, FILTER_VALIDATE_EMAIL))
my_contact_form_generate_response("error", $email_invalid);
else //email is valid
{
//validate presence of name and message
if (empty($name) || empty($message)) {
my_contact_form_generate_response("error", $missing_content);
} else //ready to go!
{
$sent = wp_mail($to, $subject, strip_tags($message), $headers);
if ($sent) my_contact_form_generate_response("success", $message_sent); //message sent!
else my_contact_form_generate_response("error", $message_unsent); //message wasn't sent
}
}
} else {
$response = "";
}
HTML:
<form action="<?php the_permalink(); ?>" class="contact" method="post">
<input type="text" placeholder="Your Name" name="message_name" value="<?php echo esc_attr($_POST['message_name']); ?>">
<input type="text" placeholder="Your Email" name="message_email" value="<?php echo esc_attr($_POST['message_email']); ?>">
<input type="text" placeholder="Your Company" name="message_company" value="<?php echo esc_attr($_POST['message_company']); ?>">
<textarea name="message_text" rows="10" placeholder="Your Message"><?php echo esc_textarea($_POST['message_text']); ?></textarea>
<button type="submit" class="contact-button" name="submitted">Submit</button>
</form>
<?php echo $response ?>
EDIT:
Sorry I forgot to add the last part of my post, what I ment was the PHP script should work the moment I hit the submit buttom. But the if ($_POST['submitted']) {} doesn't get triggered by my submit button. I was wondering why that is?

Answer 1

To me, it looks like you aren't assigning your variables to POST elements.
If you replace $email with $_POST['message_email'], $name with $_POST['message_name'], $message with $_POST['message_text'] in your first snippet you may find better luck.
Regardless, I can see quite a few unused variables in this snippet including $headers, $to, $subject, and every reporting variable used under my_contact_form_generate_*. Make sure these are also set.