detect_browser_duck_typing.js

// source: https://stackoverflow.com/a/9851769/669265
// fiddle: https://jsfiddle.net/311aLtkz/

// Opera 8.0+
var isOpera = (!!window.opr && !!opr.addons) || !!window.opera || navigator.userAgent.indexOf(' OPR/') >= 0;

// Firefox 1.0+
var isFirefox = typeof InstallTrigger !== 'undefined';

// Safari 3.0+ "[object HTMLElementConstructor]" 
var isSafari = /constructor/i.test(window.HTMLElement) || (function (p) { return p.toString() === "[object SafariRemoteNotification]"; })(!window['safari'] || safari.pushNotification);

// Internet Explorer 6-11
var isIE = /*@cc_on!@*/false || !!document.documentMode;

// Edge 20+
var isEdge = !isIE && !!window.StyleMedia;

// Chrome 1+
var isChrome = !!window.chrome && !!window.chrome.webstore;

// Blink engine detection
var isBlink = (isChrome || isOpera) && !!window.CSS;

var output = 'Detecting browsers by ducktyping:<hr>';
output += 'isFirefox: ' + isFirefox + '<br>';
output += 'isChrome: ' + isChrome + '<br>';
output += 'isSafari: ' + isSafari + '<br>';
output += 'isOpera: ' + isOpera + '<br>';
output += 'isIE: ' + isIE + '<br>';
output += 'isEdge: ' + isEdge + '<br>';
output += 'isBlink: ' + isBlink + '<br>';
document.body.innerHTML = output;