bName=navigator.appName;  bVer=parseInt(navigator.appVersion);
 if(bName=="Netscape" && bVer >= 3) version="n3";
 else if (bName=="Microsoft Internet Explorer" && bVer>=4) version="n3";
 else version="n2";
 var darkened_pics = new Array(); var lighted_pics = new Array();
 function preloadButtonSet(num,dark,light){  if(version=="n3") {
   darkened_pics[num] = new Image();  darkened_pics[num].src = dark;
   lighted_pics[num] = new Image(); lighted_pics[num].src = light; } }
 preloadButtonSet(0,"images/b-cruises-off.gif",   "images/b-cruises-on.gif");
 preloadButtonSet(1,"images/b-vacations-off.gif", "images/b-vacations-on.gif");
 preloadButtonSet(2,"images/b-tours-off.gif",     "images/b-tours-on.gif");
 function lighten(num) { if(version=="n3") {if (document.images)
   eval("document.button"+num+".src = lighted_pics["+num+"].src;");
   return false; } }
 function darken(num) { if(version=="n3") { if (document.images)
   eval("document.button"+num+".src = darkened_pics["+num+"].src;");
   return false; } }