var Win = navigator.appVersion.indexOf("Win",0) != -1;
var Mac = navigator.appVersion.indexOf("Mac",0) != -1;
   if(Mac){
   document.writeln("<link rel=\"stylesheet\" href=\"style/mac.css\" type=\"text/css\">");
   }
   else if(Win){
   document.writeln("<link rel=\"stylesheet\" href=\"style/win.css\" type=\"text/css\">");
   }