closest() polyfill

closest.js

(function (ELEMENT) {
	ELEMENT.matches = ELEMENT.matches || 
			ELEMENT.mozMatchesSelector || 
			ELEMENT.msMatchesSelector || 
			ELEMENT.oMatchesSelector || 
			ELEMENT.webkitMatchesSelector;

	ELEMENT.closest = ELEMENT.closest || function closest(selector) {
		var element = this;

		while (element) {
			if (element.matches(selector)) {
				return element;
			} else {
			    element = element.parentElement;
			}
			
		}

		return null;
	};
}(Element.prototype));