if (navigator.platform.indexOf('Mac') > -1) {

    //mac users

    if(navigator.appName.indexOf('Microsoft') > -1){

      //explorer

      document.write('<link href="./img/css/mac.css" rel="styleSheet" type="text/css">');



      }else{

      //netscape

      document.write('<link href="./img/css/mac.css" rel="styleSheet" type="text/css">');



  }



  } else {

    //windows or unix

    if (navigator.appName.indexOf('Microsoft') > -1) {

      //explorer

      document.write('<link href="./img/css/mac.css" rel="styleSheet" type="text/css">');



    } else {

      //netscape

      document.write('<link href="./img/css/win.css" rel="styleSheet" type="text/css">');



    }

  }