1 - There are several ways to pass on a message to the page you are redirecting to. One is through $_GET
like this
$message="Some message for the next page.";
$message=urlencode($message);
header("Location:page.php?message=".$message);
then on page.php
if(!empty($_GET['message']))
{
$_GET['message'];
}
similarly you can also use the session (less secure)
$_SESSION['message']='some other message';
then on page.php
if (!empty($_SESSION['message']))
{
echo $_SESSION['message'];
unset($_SESSION['message']);
}
2 - I would have to see what you are passing to your validate
function. You should do a var_dump
of $_POST
and add that to your question.
3 - It depends on your criteria. If you are just checking for emptiness its overkill. I don't know what text you need / consider valid, but a regex is a reasonable way of enforcing validation.
4 - See #2.