browser-detection.js

var isOpera = (!!window.opr && !!opr.addons) || !!window.opera || navigator.userAgent.indexOf(" OPR/") >= 0
  , isIE = /*@cc_on!@*/false || !!document.documentMode
  , isChrome = !!window.chrome && !!window.chrome.webstore;

window.__BrowserDetection = {
  // Opera 8.0+
  isOpera: isOpera,
  // Firefox 1.0+
  isFirefox: typeof InstallTrigger !== "undefined",
  // At least Safari 3+: "[object HTMLElementConstructor]"
  isSafari: Object.prototype.toString.call(window.HTMLElement).indexOf("Constructor") > 0,
  // Internet Explorer 6-11
  isIE: isIE,
  // Edge 20+
  isEdge: !isIE && !!window.StyleMedia,
  // Chrome 1+
  isChrome: isChrome,
  // Blink engine detection
  isBlink: (isChrome || isOpera) && !!window.CSS,
};