detecting mobile operating system by javascript

detectMobileOperatingSystem.js

function getMobileOperatingSystem() {
    var userAgent = navigator.userAgent || navigator.vendor || window.opera;
    if( userAgent.match( /iPad/i ) || userAgent.match( /iPhone/i ) || userAgent.match( /iPod/i ) )
    {
        return 'iOS';
    }
    else if( userAgent.match( /Android/i ) )
    {
        return 'Android';
    }
    else
    {
        return 'unknown';
    }
}
    
//another version found on internet    
var isMobile = {
    Android: function() {
        return navigator.userAgent.match(/Android/i);
    },
    BlackBerry: function() {
        return navigator.userAgent.match(/BlackBerry/i);
    },
    iOS: function() {
        return navigator.userAgent.match(/iPhone|iPad|iPod/i);
    },
    Opera: function() {
        return navigator.userAgent.match(/Opera Mini/i);
    },
    Windows: function() {
        return navigator.userAgent.match(/IEMobile/i);
    },
    any: function() {
        return (isMobile.Android() || isMobile.BlackBerry() || isMobile.iOS() || isMobile.Opera() || isMobile.Windows());
    }
};