// Preload images -
   homeOn = new Image();
   homeOn.src = "/serpenthead/images/logonav_home.gif";
   serpOn = new Image();
   serpOn.src = "/serpenthead/images/logonav_serp.gif";
   cendOn = new Image();
   cendOn.src = "/serpenthead/images/logonav_cend.gif";