nextSibling.nodeName为#text ？解决方法 _JavaScript

nextSibling.nodeName为#text ？？？

HTML code

<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html>

<head>
<script language="javascript">
    
    function change(obj)
    {
        if(obj.innerText=="[-]")
        {
            obj.innerText="[+]";
            
            //下面的alert我测试了下，当前对象的.parentNode.nextSibling.nodeName
            //应该是ul，怎么弹出显示的是#text啊？？？
            alert(obj.parentNode.nextSibling.nodeName);
            
            next(obj.parentNode).style.display = "none";
        }else{
            obj.innerText="[-]";
            next(obj.parentNode).style.display = "block";
        }
    }
    
    function next(elem) {//获得下一个元素节点
        do {
            elem = elem.nextSibling;
        } while (elem && elem.nodeType != 1);//nodetype=1是元素节点 
        return elem;
    }

</script>
<link rel="stylesheet" type="text/css" href="css.css" />
</head>

<body>
    <div>
        <p><span onclick="change(this)">[-]</span>aaa</p>
        <ul>
            <li>aaaaaa</li>
            <li>aaaaaa</li>
            <li>aaaaaa</li>
        </ul>
    <p><span onclick="change(this)">[-]</span>bbb</p>
        <ul>
            <li>bbbbbb</li>
            <li>bbbbbb</li>
            <li>bbbbbb</li>
        </ul>
    <p><span onclick="change(this)">[-]</span>ccc</p>
        <ul>
            <li>cccccc</li>
            <li>cccccc</li>
            <li>cccccc</li>
        </ul>
    </div>
</body>

</html>

------解决方案--------------------

JScript code

 function change(obj)
    {
        if(obj.innerText=="[-]")
        {
            obj.innerText="[+]";
            
            //下面的alert我测试了下，当前对象的.parentNode.nextSibling.nodeName
            //应该是ul，怎么弹出显示的是#text啊？？？
            // alert(obj.parentNode.nextSibling.nodeName);
            var test = obj.parentNode.nextSibling;
            if(test.nodeName == "text"){
                test = test.nextSibling;
            }
            alert(test.nodeName);
            
            next(obj.parentNode).style.display = "none";
        }else{
            obj.innerText="[-]";
            next(obj.parentNode).style.display = "block";
        }
    }