获取节点的两种方式：
1、通过event对象的srcElement属性；
2、通过事件源对象用this传入。
代码如下：
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title>收缩菜单 · 表单布局</title>
<script type="text/javascript">
function list(dtNode){
// var dtNode = event.srcElement;
var dlNode = dtNode.parentNode;
// alert(dtNode.nodeName+"---"+dlNode.nodeName);
var dlNodes = document.getElementsByTagName("dl");
// alert(dlNodes.length);
for(var i=0; i<dlNodes.length; i++){
if(dlNodes[i] == dlNode){
/*判断当前标题是展开还是关闭状态，默认关闭，先执行else语句*/
if(dlNode.className == "open"){
dlNode.className = "close";
}
else{
dlNode.className = "open";
}
}
else{
dlNodes[i].className = "close";
}
}
}
</script>
<style type="text/css">
dl{
overflow: hidden;
height: 18px;
}
.open{
overflow: visible;
}
.close{
overflow: hidden;
}
</style>
</head>
<!-- 获取节点的两种方式：
1、通过event对象的srcElement属性；
2、通过事件源对象用this传入
-->
<body>
<!-- 事件源是dt，但是操作的是dl -->
<dl>
<dt onclick="list(this)">今天天气好晴朗<https://img.qb5200.com/download-x/dt>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<https://img.qb5200.com/download-x/dl>
<dl>
<dt onclick="list(this)">今天天气好晴朗<https://img.qb5200.com/download-x/dt>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<https://img.qb5200.com/download-x/dl>
<dl>
<dt onclick="list(this)">今天天气好晴朗<https://img.qb5200.com/download-x/dt>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<https://img.qb5200.com/download-x/dl>
<dl>
<dt onclick="list(this)">今天天气好晴朗<https://img.qb5200.com/download-x/dt>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<https://img.qb5200.com/download-x/dl>
<dl>
<dt onclick="list(this)">今天天气好晴朗<https://img.qb5200.com/download-x/dt>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<https://img.qb5200.com/download-x/dl>
<dl>
<dt onclick="list(this)">今天天气好晴朗<https://img.qb5200.com/download-x/dt>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<https://img.qb5200.com/download-x/dl>
<dl>
<dt onclick="list(this)">今天天气好晴朗<https://img.qb5200.com/download-x/dt>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<dd>今天天气好晴朗<https://img.qb5200.com/download-x/dd>
<https://img.qb5200.com/download-x/dl>
</body>
</html>
