deadSimpleDOMDelegate.js

function delegate(el, type, selector, callback) {
  el = typeof el === 'string' ? document.querySelector(el) : el;
  if (!el) return;
  el.addEventListener(type, function(event) {
    var node = event.target;
    while (node && node !== el) {
      if (node.matches(selector))
        callback.call(node, event);
      node = node.parentNode;
    }
  });
}