knockout实现嵌套循环绑定

实现效果如下：

代码：

<script type="text/javascript" src="knockout-2.2.0.js"></script>  <ul data-bind="foreach: { data: categories, as: 'category' }">      <li>          <ul data-bind="foreach: { data: items, as: 'item' }">              <li>                  <span data-bind="text: category.name"></span>:                  <span data-bind="text: item"></span>              </li>          </ul>      </li>  </ul>     <script>     var viewModel = {         categories: ko.observableArray([             { name: 'Fruit', items: ['Apple', 'Orange', 'Banana'] },             { name: 'Vegetables', items: ['Celery', 'Corn', 'Spinach'] }         ])     };     ko.applyBindings(viewModel);  </script>