``` function getOSname() { var e = "Unknown"; if (window.navigator.userAgent.indexOf("Windows NT 10.0") != -1) e = "Windows 10"; if (window.navigator.userAgent.indexOf("Windows NT 6.2") != -1) e = "Windows 8"; if (window.navigator.userAgent.indexOf("Windows NT 6.1") != -1) e = "Windows 7"; if (window.navigator.userAgent.indexOf("Windows NT 6.0") != -1) e = "Windows Vista"; if (window.navigator.userAgent.indexOf("Windows NT 5.1") != -1) e = "Windows XP"; if (window.navigator.userAgent.indexOf("Windows NT 5.0") != -1) e = "Windows 2000"; if (window.navigator.userAgent.indexOf("Mac") != -1) e = "Mac/iOS"; if (window.navigator.userAgent.indexOf("X11") != -1) e = "UNIX"; if (window.navigator.userAgent.indexOf("Linux") != -1) e = "Linux"; return e } ```