为什么没有结果 ？？大神帮帮忙
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>nextSibling</title>
</head>
<body>
<ul id="u1">
<li id="a">javascript</li>
<li id="b">jquery</li>
<li id="c">html</li>
</ul>
<ul id="u2">
<li id="d">css3</li>
<li id="e">php</li>
<li id="f">java</li>
</ul>
<script type="text/javascript">
function get_nextSibling(n){
var x=n.nextSibling;
while (x && x.nodeType!=1){
x=x.nextSibling;
}
return x;
}
var x=document.getElementsByTagName("li")[0];
document.write(x.nodeName);
document.write(" = ");
document.write(x.innerHTML);
var y=get_nextSibling(x);
if(y!=null){
document.write("<br />nextsibling: ");
document.write(y.nodeName);
document.write(" = ");
document.write(y.innerHTML);
}else{
document.write("<br>已经是最后一个节点");
}
function get_perviousSibling(i){
var h=i.perviousSibling;
while (h && h.nodeType!=1){
h=h.perviousSibling;
}
return h;
}
var k=document.getElementByTagName("li")[2];
document.write(k.nodeName);
document.write(" = ");
document.write(k.innerHTML);
var m=get_perviousSibling(k);
if(m!=null){
document.write("<br />perviousSibling:");
document.write(m.nodeName);
document.write(" = ");
document.write(m.innerHTML);
}else{
document.write("<br>已经是第一个节点");
}
</script>
</body>
</html>
为什么后面的想要得到前一个节点得不到结果？？大神来看一看啊!!!
