smooth-scroll/src/js/smooth-scroll/_closest.polyfill.js

Animate scrolling to anchor links

/**
 * closest() polyfill
 * @link https://developer.mozilla.org/en-US/docs/Web/API/Element/closest#Polyfill
 */
if (window.Element && !Element.prototype.closest) {
	Element.prototype.closest = function(s) {
		var matches = (this.document || this.ownerDocument).querySelectorAll(s),
			i,
			el = this;
		do {
			i = matches.length;
			while (--i >= 0 && matches.item(i) !== el) {}
		} while ((i < 0) && (el = el.parentElement));
		return el;
	};
}