<div class="diskmain">  <ul id="folder">    <li><span class=‘documents‘><a href=‘javascript:void(0)‘ id=‘1‘ onclick=‘getid(this);‘>分类A</a></span></li>    <li><span class=‘lists‘><a href=‘javascript:void(0)‘ id=‘2‘ onclick=‘getid(this);‘>分类B</a></span></li>    <li><span class=‘pictures‘><a href=‘javascript:void(0)‘ id=‘3‘ onclick=‘getid(this);‘>分类C</a></span></li>    <li><span class=‘share‘><a href=‘javascript:void(0)‘ id=‘4‘ onclick=‘getid(this);‘>分类D</a></span></li>  </ul></div><script>function getid(a){alert(a.id)};</script>