I want an exit popunder like on this site:
http://products.mercola.com/krill/

I found the script in the source:
Code:
<script type='text/javascript'>

function readCookie(name) {
 var nameEQ = name + "=";
 var ca = document.cookie.split(';');
 for(var i=0;i < ca.length;i++) {
  var c = ca[i];
  while (c.charAt(0)==' ') c = c.substring(1,c.length);
  if (c.indexOf(nameEQ) == 0) 
   return c.substring(nameEQ.length,c.length);
 }
 return '';
}

  if( (readCookie('Mercola')== null) || (readCookie('Mercola') != 'subscribed') )
  {

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}
</script>
It works great, but i can't figure out how to modify it for my website...
Is it encrypted? how to use it?