How to Detect the Operating System (OS) Using JavaScript

Sometimes it is necessary to determine the user’s operating system. To use different CSS styles for different OS, or for some analytics, or for other purposes. There are various plugins or libraries for detecting the operating system, but for this task you can do without a third-party plugin. If you don’t need to determine the operating system version, but only its name, then you can write the OS detection code yourself.

JavaScript

function detectOS() {
    const platform = navigator.platform.toLowerCase(),
        iosPlatforms = ['iphone', 'ipad', 'ipod', 'ipod touch'];

    if (platform.includes('mac')) return 'MacOS';
    if (iosPlatforms.includes(platform)) return 'iOS';
    if (platform.includes('win')) return 'Windows';
    if (/android/.test(navigator.userAgent.toLowerCase())) return 'Android';
    if (/linux/.test(platform)) return 'Linux';

    return 'unknown';
}

This code does not detect all the operating systems in the world, but only the main ones. I think such code will be easy to modify if there is a need to add another OS.

You can see an example of the code working on Codepen: https://codepen.io/igorrybalko/pen/vEBvPgm