check for internet explorer browser in javascript

// Internet Explorer 6-11
const isIE = !!document.documentMode;var ua = window.navigator.userAgent;
var msie = ua.indexOf('MSIE ');
if (msie > 0) {
  // IE 10 or older => return version number
  return parseInt(ua.substring(msie + 5, ua.indexOf('.', msie)), 10);
}

var ua = window.navigator.userAgent;
var trident = ua.indexOf('Trident/');
if (trident > 0) {
  // IE 11 => return version number
  var rv = ua.indexOf('rv:');
  return parseInt(ua.substring(rv + 3, ua.indexOf('.', rv)), 10);
}

var ua = window.navigator.userAgent;
var edge = ua.indexOf('Edge/');
if (edge > 0) {
  // Edge (IE 12+) => return version number
  return parseInt(ua.substring(edge + 5, ua.indexOf('.', edge)), 10);
}