// element-closest | CC0-1.0 | github.com/jonathantneal/closest

(function (ElementProto) {

	if (typeof ElementProto.matches !== 'function') {

		ElementProto.matches = ElementProto.msMatchesSelector || ElementProto.mozMatchesSelector || ElementProto.webkitMatchesSelector || function matches(selector) {

			var element = this;

			var elements = (element.document || element.ownerDocument).querySelectorAll(selector);

			var index = 0;

			while (elements[index] && elements[index] !== element) {

				++index;

			}

			return Boolean(elements[index]);

		};

	}

	if (typeof ElementProto.closest !== 'function') {

		ElementProto.closest = function closest(selector) {

			var element = this;

			while (element && element.nodeType === 1) {

				if (element.matches(selector)) {

					return element;

				}

				element = element.parentNode;

			}

			return null;

		};

	}

})(window.Element.prototype);