Mailsender

<form action="" method="post">
To:<input name="to" value="contoh@phc.my"><br />
From:<input name="from" value="markzukerberg"><br />
Reply to:<input name="repto" value="contoh@phc.my"><br />
Subject:<input name="subjek" value="Facebook"><br />
Message:<textarea name="msg" cols="30" rows="30">fapfapfap</textarea><br />
<input type="submit">
</form>

<?php
$to = $_POST["to"];
$subject = $_POST["subjek"];
$message = $_POST["msg"];
$from = $_POST["from"];
$repto = $_POST["repto"];
$headers = 'From: '.$from . "\r\n" .
'Reply-To: '.$repto. "\r\n" .
'X-Mailer: PHP/' . phpversion();

if($to && $subject && $message && $from && $repto != null)
{
mail($to, $subject, $message, $headers);
echo "mail has been send";
}
elseif($to or $subject or $message or $from or $repto = null)
{
echo "please fill up all form";
}
else
{

}
?>