front__coursera-responsive-design/js/behaviours.js

/**
 * State has already changed when this handler is called.
 *
 * @param event
 */
function handleCheckboxClick(event) {
  var $target = $(event.target);
  var currentState = $target.prop("checked");
  var $item = $($target.parentsUntil("ul")[2]);
  var newClass = currentState ? "list-group-item-success" : "list-group-item-warning";
  var oldClass = currentState ? "list-group-item-warning" : "list-group-item-success";
  console.log($item.constructor.prototype);
  $item.addClass(newClass).removeClass(oldClass);
}

$(function () {
  $("input[type='checkbox']").click(handleCheckboxClick);
});