flexi-js/src/poly/element.closest.js

A responsive and flexible css scheme.

/** polyfil */
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;
  };
}