function log_out()
{
 ht = document.getElementsByTagName("html");
 ht[0].style.filter = "progid:DXImageTransform.Microsoft.BasicImage(grayscale=1)";
 if (confirm('Are you sure you want to log out?'))
 {
  return true;
 }
 else
 {
  ht[0].style.filter = "";
  return false;
 }
}