closest.js

/**
 * Vanilla JS implementation of $.closest()
 *
 * @param {Node|HTMLElement|*} el Starting point element
 * @param {String} selector Selector to match parent element against
 * @returns {*} Element node if found, otherwise null
 */
function closestEl(el, selector) {
    var matchesSelector = el.matches || el.matchesSelector || el.msMatchesSelector || el.mozMatchesSelector || el.webkitMatchesSelector || el.oMatchesSelector;

    while (el) {
        if (matchesSelector.call(el, selector)) {
            return el;
        } else {
            el = el.parentNode;
        }
    }

    return null;
};