给定下面的 HTML 代码:
<div id=”wrapper”>
<div class=”wText”>…</div>…<!—more wText items here -->
<div class=”wImg”>…</div>…<!—more wImg items here -->
<div class=”wVideo”>…</div>…<!—more wVideo items here -->
</div>
怎么能够取得 ”wrapper” 中全部项的集合?