Make a div appear only when needed

[KijakA73]

I am using a as an alert bar on my page. I have a logout message appearing after the user logs out. But the div shows up all the time. I want it to show up only once the user logs out. my code is as such that makes the div read the message \[code\] <?phpif ($_GET['msg']){ echo '<div id="success_message">' . base64_decode(urldecode($_GET['msg'])) . '</div>';}?> \[/code\]I figure we could add something to this code to make it appear after the page is visited after the logout. Any ideas?