JavaScript: OS detection

Operating System

Question: How do I detect the operating system on the client machine?

Answer: To detect the operating system on the client machine, your script should analyze the navigator.appVersion string. Below is a simple example of a script that sets the variable OSName to reflect the actual client OS.

// This script sets OSName variable as follows:
// "Windows"    for all versions of Windows
// "MacOS"      for all versions of Macintosh OS
// "Linux"      for all versions of Linux
// "UNIX"       for all other UNIX flavors 
// "Unknown OS" indicates failure to detect the OS

var OSName="Unknown OS";
if (navigator.appVersion.indexOf("Win")!=-1) OSName="Windows";
if (navigator.appVersion.indexOf("Mac")!=-1) OSName="MacOS";
if (navigator.appVersion.indexOf("X11")!=-1) OSName="UNIX";
if (navigator.appVersion.indexOf("Linux")!=-1) OSName="Linux";

document.write('Your OS: '+OSName);

On your system, this script yields the following result:

(To get more detailed OS information, your script should perform a more sophisticated analysis of the navigator.appVersion string, but the idea would be the same.)