Function on

06.Router/basic/js/vue.js:1271–1273

* Add event listener shorthand. * * @param {Element} el * @param {String} event * @param {Function} cb * @param {Boolean} [useCapture]

(el, event, cb, useCapture)

   */

  function on(el, event, cb, useCapture) {
    el.addEventListener(event, cb, useCapture);
  }

  /**
   * Remove event listener shorthand.