Set the page to HTTPS!
If you know the HTTPS pages force them to HTTPS.
PHP Example
<?php
if( $_SERVER['SERVER_PORT'] == 80) {
header('Location:https://'.$_SERVER['HTTP_HOST'].dirname($_SERVER['PHP_SELF']).'/'.basename($_SERVER['PHP_SELF']));
die();
}
?>
<html>
<style type="text/css">
<!--
.style1 {
color: #00FF00;
font-weight: bold;
}
-->
</style>
<p>Hello world</p>
<p>HTTPS security = <span class="style1"><?php echo((isset($_SERVER["HTTPS"]))?$_SERVER["HTTPS"]:"") ?></span></p>
</html>
Change == 80 to 443 and 'Location:... to 'Location:... will reverse