var n6 = (navigator.userAgent.indexOf("Mozilla/5") >= 0);
var ns = (navigator.appName == "Netscape");
var win = (navigator.userAgent.indexOf("Win") >= 0);
var mac = (navigator.userAgent.indexOf("Mac") >= 0);
var ie = (navigator.userAgent.indexOf("MSIE") >= 0);
var ver = (navigator.appVersion.charAt(0))

if (mac) {
  if(ie || n6) {
    fName = "./css/style.css";
  } else if (ns) {
    fName = "./css/style_top_nn.css";
  }
} else {
  if (ie || n6) {
    fName = "./css/style.css";
  } else if (ns) {
    fName = "./css/style_top_nn.css";
  }
}

if (fName != null) { 
  document.write("<link rel=\"stylesheet\" href=\""+fName+"\" type=\"text/css\">");
}