}
    // Polyfill Element.closest()
    if (!Element.prototype.closest) {
        Element.prototype.closest = function (s) {
            var el = this;
            if (!document.documentElement.contains(el)) return null;
            do {
                if (typeof el.matches === "function" && el.matches(s)) return el;
                el = el.parentElement || el.parentNode;
            } while (el !== null);