fValidVer = 
   (((navigator.appName == "Netscape") && 
   (parseInt(navigator.appVersion) >= 3 )) || 

   ((navigator.appName == "Opera") && 
   (parseInt(navigator.appVersion) >= 6 )) ||

   ((navigator.appName == "Microsoft Internet Explorer") && 
   (parseInt(navigator.appVersion) >= 4 )));

  if (document.images){
   <!--BUTTONS-->
   var aboutus_normal = new Image;
   aboutus_normal.src = "images/button-aboutus.gif";
   aboutus_hover = new Image;
   aboutus_hover.src = "images/button-aboutus-hover.gif";
   
   var contact_normal = new Image;
   contact_normal.src = "images/button-contact.gif";
   contact_hover = new Image;
   contact_hover.src = "images/button-contact-hover.gif";

   var arrivals_normal = new Image;
   arrivals_normal.src = "images/button-arrivals.gif";
   arrivals_hover = new Image;
   arrivals_hover.src = "images/button-arrivals-hover.gif";

   var top_normal = new Image;
   top_normal.src = "images/button-top.gif";
   top_hover = new Image;
   top_hover.src = "images/button-top-hover.gif";   

   var closewindow_normal = new Image;
   closewindow_normal.src = "images/button-closewindow.gif";
   closewindow_hover = new Image;
   closewindow_hover.src = "images/button-closewindow-hover.gif";   

   var siteinfo_normal = new Image;
   siteinfo_normal.src = "images/button-siteinfo.gif";
   var siteinfo_hover = new Image;
   siteinfo_hover.src = "images/button-siteinfo-hover.gif";  
  }

  function Swap(image1, image2) {
   if (document.images)
   	document.images[image1].src = eval(image2 + ".src");
  }