Function to delegate events. Can be used with any css selector

delegate.js

function delegate(element, eventType, selector, callback, bubble) {
  var selectorObj = getSelectorType(selector);
  var callbackFn;

  selector = selectorObj.value;

  switch (selectorObj.type) {
  case 'tag':
    callbackFn = tagSelector;
    break;
  case 'class':
    callbackFn = classSelector;
    break;
  default:
    callbackFn = anySelector;
    break;
  }



  function getSelectorType(selector) {
    selector = selector.replace(/^\s\s*/, '').replace(/\s\s*$/, '');
    if (/^[a-z]+$/i.test(selector)) {
      return {
        type: 'tag',
        value: selector
      };
    } else if (/^\.[a-z]+$/.test(selector)) {
      return {
        type: 'class',
        value: selector.replace('.', '')
      };
    } else {
      return {
        type: 'other',
        value: selector
      }
    }
  }



  function tagSelector(evt) {
    var el = evt.target;
    while (el !== evt.currentTarget) {
      if (el.nodeName.toLowerCase() === selector) {
        callback.call(el, evt);
        return;
      } else {
        el = el.parentNode;
      }
    }
  }



  function classSelector(evt) {
    var el = evt.target;
    while (el !== evt.currentTarget) {
      if (el.classList.contains(selector)) {
        callback.call(el, evt);
        return;
      } else {
        el = el.parentNode;
      }
    }
  }



  function anySelector(evt) {
    var el = evt.target;
    var currentEl;
    var targets = element.querySelectorAll(selector);

    while (el !== evt.currentTarget) {
      currentEl = elementInList(targets, el);
      if (currentEl) {
        callback.call(currentEl, evt);
        return;
      } else {
        el = el.parentNode;
      }
    }
  }



  function elementInList(list, element) {
    for (var i = 0, l = list.length; i < l; i++) {
      if (element === list[i]) {
        return list[i];
      }
    }
    return false;
  }

  element.addEventListener(eventType, callbackFn, typeof bubble === undefined ? false : bubble);
}