DTX

<ul id="list">
    <li class="yes">1</li>
    <li class="no">2</li>
    <li class="no">3</li>
    <li>...</li>
    <li class="yes">100</li>
</ul>

function on(elSelector, eventName, selector, fn) {
    var element = document.querySelector(elSelector);

    element.addEventListener(eventName, function(event) {
        var possibleTargets = element.querySelectorAll(selector);
        var target = event.target;

        for (var i = 0, l = possibleTargets.length; i < l; i++) {
            var el = target;
            var p = possibleTargets[i];

            while(el && el !== element) {
                if (el === p) {
                    return fn.call(p, event);
                }

                el = el.parentNode;
            }
        }
    });
}

on('#list', 'click', '.yes', function(e) {
    // this function is only called, when a list item with 'yes' class is called
    console.log(e.target); // this is the clicked list item
});

$('ul.news-list').on('click',' div > a.button', function() {
// 
});

$('body').on('click', '.add-copy__input-file', handlerFunc);

var obj = {
  div: $('div'),
  onClick: function () {
      counter++;
      this.div.text(counter);
  },
  init: function() {
    $('div:nth-child(2)').click(this.onClick.bind(this));
  }
};

Почему не работает :last-child селектор?