// Opera 8.0+
var isOpera = (!!window.opr && !!opr.addons) || !!window.opera || navigator.userAgent.indexOf(‘ OPR/’) >= 0;
// Firefox 1.0+
var isFirefox = typeof InstallTrigger !== ‘undefined’;
// At least Safari 3+: «[object HTMLElementConstructor]»
var isSafari = Object.prototype.toString.call(window.HTMLElement).indexOf(‘Constructor’) > 0;
// 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:

‘;
output += ‘isFirefox: ‘ + isFirefox + ‘
‘;
output += ‘isChrome: ‘ + isChrome + ‘
‘;
output += ‘isSafari: ‘ + isSafari + ‘
‘;
output += ‘isOpera: ‘ + isOpera + ‘
‘;
output += ‘isIE: ‘ + isIE + ‘
‘;
output += ‘isEdge: ‘ + isEdge + ‘
‘;
output += ‘isBlink: ‘ + isBlink + ‘
‘;
document.body.innerHTML = output;