Ludwig gave a very appropriate answer to this question in this answer. This is one of the best and the most appropriate methods to check if the user is on mobile or which os is he using.
Check out his fiddle here
(function (window) {
{
var unknown = '-';
// screen
var screenSize = '';
if (screen.width) {
width = (screen.width) ? screen.width : '';
height = (screen.height) ? screen.height : '';
screenSize += '' + width + " x " + height;
}
// browser
var nVer = navigator.appVersion;
var nAgt = navigator.userAgent;
var browser = navigator.appName;
var version = '' + parseFloat(navigator.appVersion);
var majorVersion = parseInt(navigator.appVersion, 10);
var nameOffset, verOffset, ix;
// Opera
if ((verOffset = nAgt.indexOf('Opera')) != -1) {
browser = 'Opera';
version = nAgt.substring(verOffset + 6);
if ((verOffset = nAgt.indexOf('Version')) != -1) {
version = nAgt.substring(verOffset + 8);
}
}
// Opera Next
if ((verOffset = nAgt.indexOf('OPR')) != -1) {
browser = 'Opera';
version = nAgt.substring(verOffset + 4);
}
// Edge
else if ((verOffset = nAgt.indexOf('Edge')) != -1) {
browser = 'Microsoft Edge';
version = nAgt.substring(verOffset + 5);
}
// MSIE
else if ((verOffset = nAgt.indexOf('MSIE')) != -1) {
browser = 'Microsoft Internet Explorer';
version = nAgt.substring(verOffset + 5);
}
// Chrome
else if ((verOffset = nAgt.indexOf('Chrome')) != -1) {
browser = 'Chrome';
version = nAgt.substring(verOffset + 7);
}
// Safari
else if ((verOffset = nAgt.indexOf('Safari')) != -1) {
browser = 'Safari';
version = nAgt.substring(verOffset + 7);
if ((verOffset = nAgt.indexOf('Version')) != -1) {
version = nAgt.substring(verOffset + 8);
}
}
// Firefox
else if ((verOffset = nAgt.indexOf('Firefox')) != -1) {
browser = 'Firefox';
version = nAgt.substring(verOffset + 8);
}
// MSIE 11+
else if (nAgt.indexOf('Trident/') != -1) {
browser = 'Microsoft Internet Explorer';
version = nAgt.substring(nAgt.indexOf('rv:') + 3);
}
// Other browsers
else if ((nameOffset = nAgt.lastIndexOf(' ') + 1) < (verOffset = nAgt.lastIndexOf('/'))) {
browser = nAgt.substring(nameOffset, verOffset);
version = nAgt.substring(verOffset + 1);
if (browser.toLowerCase() == browser.toUpperCase()) {
browser = navigator.appName;
}
}
// trim the version string
if ((ix = version.indexOf(';')) != -1) version = version.substring(0, ix);
if ((ix = version.indexOf(' ')) != -1) version = version.substring(0, ix);
if ((ix = version.indexOf(')')) != -1) version = version.substring(0, ix);
majorVersion = parseInt('' + version, 10);
if (isNaN(majorVersion)) {
version = '' + parseFloat(navigator.appVersion);
majorVersion = parseInt(navigator.appVersion, 10);
}
// mobile version
var mobile = /Mobile|mini|Fennec|Android|iP(ad|od|hone)/.test(nVer);
// cookie
var cookieEnabled = (navigator.cookieEnabled) ? true : false;
if (typeof navigator.cookieEnabled == 'undefined' && !cookieEnabled) {
document.cookie = 'testcookie';
cookieEnabled = (document.cookie.indexOf('testcookie') != -1) ? true : false;
}
// system
var os = unknown;
var clientStrings = [
{s:'Windows 10', r:/(Windows 10.0|Windows NT 10.0)/},
{s:'Windows 8.1', r:/(Windows 8.1|Windows NT 6.3)/},
{s:'Windows 8', r:/(Windows 8|Windows NT 6.2)/},
{s:'Windows 7', r:/(Windows 7|Windows NT 6.1)/},
{s:'Windows Vista', r:/Windows NT 6.0/},
{s:'Windows Server 2003', r:/Windows NT 5.2/},
{s:'Windows XP', r:/(Windows NT 5.1|Windows XP)/},
{s:'Windows 2000', r:/(Windows NT 5.0|Windows 2000)/},
{s:'Windows ME', r:/(Win 9x 4.90|Windows ME)/},
{s:'Windows 98', r:/(Windows 98|Win98)/},
{s:'Windows 95', r:/(Windows 95|Win95|Windows_95)/},
{s:'Windows NT 4.0', r:/(Windows NT 4.0|WinNT4.0|WinNT|Windows NT)/},
{s:'Windows CE', r:/Windows CE/},
{s:'Windows 3.11', r:/Win16/},
{s:'Android', r:/Android/},
{s:'Open BSD', r:/OpenBSD/},
{s:'Sun OS', r:/SunOS/},
{s:'Linux', r:/(Linux|X11)/},
{s:'iOS', r:/(iPhone|iPad|iPod)/},
{s:'Mac OS X', r:/Mac OS X/},
{s:'Mac OS', r:/(MacPPC|MacIntel|Mac_PowerPC|Macintosh)/},
{s:'QNX', r:/QNX/},
{s:'UNIX', r:/UNIX/},
{s:'BeOS', r:/BeOS/},
{s:'OS/2', r:/OS\/2/},
{s:'Search Bot', r:/(nuhk|Googlebot|Yammybot|Openbot|Slurp|MSNBot|Ask Jeeves\/Teoma|ia_archiver)/}
];
for (var id in clientStrings) {
var cs = clientStrings[id];
if (cs.r.test(nAgt)) {
os = cs.s;
break;
}
}
var osVersion = unknown;
if (/Windows/.test(os)) {
osVersion = /Windows (.*)/.exec(os)[1];
os = 'Windows';
}
switch (os) {
case 'Mac OS X':
osVersion = /Mac OS X (10[\.\_\d]+)/.exec(nAgt)[1];
break;
case 'Android':
osVersion = /Android ([\.\_\d]+)/.exec(nAgt)[1];
break;
case 'iOS':
osVersion = /OS (\d+)_(\d+)_?(\d+)?/.exec(nVer);
osVersion = osVersion[1] + '.' + osVersion[2] + '.' + (osVersion[3] | 0);
break;
}
// flash (you'll need to include swfobject)
/* script src="//ajax.googleapis.com/ajax/libs/swfobject/2.2/swfobject.js" */
var flashVersion = 'no check';
if (typeof swfobject != 'undefined') {
var fv = swfobject.getFlashPlayerVersion();
if (fv.major > 0) {
flashVersion = fv.major + '.' + fv.minor + ' r' + fv.release;
}
else {
flashVersion = unknown;
}
}
}
window.jscd = {
screen: screenSize,
browser: browser,
browserVersion: version,
browserMajorVersion: majorVersion,
mobile: mobile,
os: os,
osVersion: osVersion,
cookies: cookieEnabled,
flashVersion: flashVersion
};
}(this));
alert(
'OS: ' + jscd.os +' '+ jscd.osVersion + '\n' +
'Browser: ' + jscd.browser +' '+ jscd.browserMajorVersion +
' (' + jscd.browserVersion + ')\n' +
'Mobile: ' + jscd.mobile + '\n' +
'Flash: ' + jscd.flashVersion + '\n' +
'Cookies: ' + jscd.cookies + '\n' +
'Screen Size: ' + jscd.screen + '\n\n' +
'Full User Agent: ' + navigator.userAgent
);
All credit goes to Ludwig