text: // 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'] || (typeof safari !== 'undefined' && window['safari'].pushNotification));
  
  // Internet Explorer 6-11
  var isIE = /*@cc_on!@*/false || !!document.documentMode;
  
  // Edge 20+
  var isEdge = !isIE && !!window.StyleMedia;
  
  // Chrome 1 - 79
  var isChrome = !!window.chrome && (!!window.chrome.webstore || !!window.chrome.runtime);
  
  // Edge (based on chromium) detection
  var isEdgeChromium = isChrome && (navigator.userAgent.indexOf("Edg") != -1);
  
  // Blink engine detection
  var isBlink = (isChrome || isOpera) && !!window.CSS;