Detect Internet Explorer/Edge with JavaScript userAgent string sniffing. Silly spoofers.

is-ms-browser.js

var isIE = (function() {
    var ua = navigator.userAgent,
        ieMatches = [/Edge\/[0-9\.]+$/, /MSIE/, /Trident\/[0-9\.]+/];

    for(var i = 0, len = ieMatches.length; i < len; i++) {
        if (ua.match(ieMatches[i])) {
            return true;
        }
    }

    return false;
}());