为什么一共有7个节点，最后一栏只显示4个？
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
</head>
<body>
<div>
javascript
<p>javascript</p>
<div>jQuery</div>
<h5>PHP</h5>
</div>
<script type="text/javascript">
var x = document.getElementsByTagName('div')[0].childNodes;
document.write('div的子节点数：' + x.length + '<br />');
document.write('各个节点的类型：' + '<br />');
for(var i = 0;i < x.length;i++){
document.write(x[i].nodeType + "\t");
}
document.write('<br />');
document.write('各个节点的名称：' + '<br />');
for(var i = 0;i < x.length;i++){
document.write(x[i].nodeName + "\t");
}
document.write('<br />');
document.write('各个节点的值：' + '<br />');
for(var i = 0;i < x.length;i++){
document.write(x[i].nodeValue + "\t");
}
</script>
</body>
</html>
