不知道怎么显示出来了，反正写完了😂
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
</head>
<body>
<ul id="con">
<li id="lesson1">javascript
<ul>
<li id="tcon"> 基础语法</li>
<li>流程控制语句</li>
<li>函数</li>
<li>事件</li>
<li>DOM</li>
</ul>
</li>
<li id="lesson2">das</li>
<li id="lesson3">dadf</li>
<li id="lesson4">HTML/CSS
<ul>
<li>文字</li>
<li>段落</li>
<li>表单</li>
<li>表格</li>
</ul>
</li>
</ul>
<script type="text/javascript">
var mylist = document.getElementById("tcon");
var aa = mylist.parentNode.parentNode.parentNode.childNodes[7];
var bb = aa.childNodes[1];
// document.write(bb.nodeName+bb.nodeType+bb.nodeValue)
var ddd = bb.childNodes;
for (i = 0; i < ddd.length; i++) {
var cc = bb.childNodes[i];
document.write(cc.textContent + "<br>")
}
</script>
</body>
</html>
😂
