if(navigator.appName=="Netscape"){
       if(navigator.appVersion.indexOf("Mac")!=-1)
          document.write('<link rel="stylesheet" type="text/css" href="./css/mac_nn.css" title="fontproperty">');

       else if(navigator.appVersion.indexOf("Win")!=-1)
          document.write('<link rel="stylesheet" type="text/css" href="./css/win_nn.css" title="fontproperty">');
}

     else if(navigator.appName=="Microsoft Internet Explorer"){
       if(navigator.appVersion.indexOf("Mac")!=-1)
          document.write('<link rel="stylesheet" type="text/css" href="./css/mac_ie.css" title="fontproperty">');

       else if(navigator.appVersion.indexOf("Win")!=-1)
          document.write('<link rel="stylesheet" type="text/css" href="./css/win_ie.css" title="fontproperty">');
	 }