$ event delegation

delegate.js

function $(sel) {
  if (!sel) {
    return $.body;
  }
  var r = document.querySelectorAll(sel);
  return r.length == 1 ? r[0] : Array.prototype.slice.call(r);
}

$.doc = document;
$.body = document.body;
$.win = window;

$.matches = function(el, sel) {
  var matchesSelector = el.webkitMatchesSelector || el.mozMatchesSelector ||
                        el.oMatchesSelector || el.matchesSelector;
  return matchesSelector.call(el, sel);
};

$.delegate = function(type, sel, handler) {
  /*
    Usage:

      $.delegate('submit', 'form', function() {
        alert('thanks, bro!');
      });

  */
  document.addEventListener(type, function(e) {
    var parent = e.target;
    while (parent && parent !== document) {
      if ($.matches(parent, sel)) {
        handler(e);
      }
      parent = parent.parentNode;
    }
  }, false);
};