Detect browsers

detect-browsers.js

/**
 * Detect browsers
 */
// Opera
var isOpera =
    (navigator.userAgent.indexOf('Opera') || navigator.userAgent.indexOf('OPR')) != -1;
// Firefox
var isFirefox = navigator.userAgent.indexOf('Firefox') != -1;
// Safari
var isSafari = navigator.userAgent.indexOf('Safari') != -1;
// Internet Explorer 6-11
var isIE = /*@cc_on!@*/ false || !!document.documentMode;
// Edge 20+
var isEdge = !isIE && !!window.StyleMedia;
// Chrome
var isChrome = navigator.userAgent.indexOf('Chrome') != -1;
// Facebook or Instagram
var fbOrInstagram =
    navigator.userAgent.indexOf('Instagram') != -1 ||
    (navigator.userAgent.match(/(iPod|iPhone|iPad)/) &&
        navigator.userAgent.match(/FBAV|FBBV|FBAN/i));
//IE 9+
var ie10AndBelow = navigator.userAgent.indexOf('MSIE') != -1;
var isIE10 = navigator.appVersion.indexOf('MSIE 10.') != -1;