I have created a user registration form using PHP/smarty. The form posts back to itself since I don't know of any reason not to do it this way. The problem here is that if the user refreshes the welcome page, the code will attempt to recreate the account. What is the best way to do this from both a user and security perspective?
if (isset($_POST['submit'])) {
/* Create customer account */
$smarty->display($welcome_template);
} else {
$smarty->display($form_template);
}