Needed: show message once at the top script

[qwikad.com]

I need something similar to what http://monster.com has. If you visit it you will notice how the whole page is pushed down by a yellow bar with a text at the top of the page. It's cookie based and once it's closed it doesn't show up again.

I found drop down boxes, sticky notes, etc. scripts on DD, but nothing similar to this one.

Can you guys point me in the right direction where I can find a script like that? Or maybe you have one in your own library?

Thank you!

[molendijk]

<script>
var alertmessage="This is an alert."

function prompt_once_per_session()
{
if( !/(^|\s|;)seenAlert=yes(;|\s|$)/.test(document.cookie))
{if( !confirm(alertmessage+'\n\nClick on OK if you don`t want this message to show again.\n\nClick on CANCEL if you want this message to show each time you load this page.') )
{}
else {document.cookie="seenAlert=yes";}
}
}

if ( typeof window.addEventListener != "undefined" )
window.addEventListener( "load", prompt_once_per_session, false );
else if ( typeof window.attachEvent != "undefined" )
window.attachEvent( "onload", prompt_once_per_session);
else {
if ( window.onload != null ) {
var oldOnload = window.onload;
window.onload = function ( e ) {
oldOnload( e );
prompt_once_per_session();
};
}
else
window.onload = prompt_once_per_session;
}
</script>

[qwikad.com]

molendijk, this is just another popup. I need something that will work like here: http://monster.com

Notice the yellow bar that pushes the site down...

[molendijk]

I don't see a yellow bar. But couldn't you just create one with a close button in it? It could be a div with id="show_once". Then using onclick="document.getElementById('show_once').style.display='none'" on the button will hide the div. No cookies needed, I think.