var is_iphone = navigator.userAgent.indexOf ("iPhone", 0);
var is_ipad = navigator.userAgent.indexOf ("iPad", 0);
var  is_ipod = navigator.userAgent.indexOf ("iPod", 0);
if ((is_iphone & is_ipod &is_ipad) > -1) {
document.write ( '<link rel="stylesheet" type="text/css" href="css/style2.css">' ); }
else {
document.write ( '<link rel="stylesheet" type="text/css" href="css/style.css">' ); }