var os = navigator.platform.toLowerCase();
var bt = navigator.userAgent.toLowerCase();

var is_nav  = ((bt.indexOf('mozilla')!=-1) && (bt.indexOf('spoofer')==-1)
  && (bt.indexOf('compatible') == -1) && (bt.indexOf('opera')==-1)
  && (bt.indexOf('webtv')==-1) && (bt.indexOf('hotjava')==-1));

if(is_nav) {
  if(os.indexOf('mac')!=-1) {
   // alert('mac nav '+bt);
    document.write('<link rel="stylesheet" type="text/css" href="/ngexplorer/ax/main_mac_ns.css">');
  } else if(os.indexOf('win')!=-1) {
   // alert('win nav '+bt);
    document.write('<link rel="stylesheet" type="text/css" href="/ngexplorer/ax/main_win_ns.css">');
  } else {
    //alert('other nav '+bt);
    document.write('<link rel="stylesheet" type="text/css" href="/ngexplorer/ax/main.css">');
  }
}
else {
 // alert('not nav '+bt);
  document.write('<link rel="stylesheet" type="text/css" href="/ngexplorer/ax/main.css">');
}