<form
<form action="register.php" method="post" name=register>
<input type="submit" class="bginput" value="Agree">
<input type="submit" name="Submit" class="bginput" value="Agree">
$footer
<script> document.forms.register.Submit.disabled =true; window.setTimeout("Timer()", 15000); function Timer() { document.forms.register.Submit.disabled =false; }; </script>