为什么 nodename 打印“root”，但 nodeValue 返回多个子节点中的所有值。
运行此代码，回显将返回
"父节点的名字是root 它的值是Text value 11111 Empty text value 2222 space text value 3333 "
第二个回声将返回这个
"子节点为空格，其值为空格文本值3333"
<?php
$xmldoc=
'<?xml version="1.0" ?><root>
<text>Text value 11111</text>
<none/>
<empty>Empty text value 2222</empty>
<space>space text value 3333 </space>
</root>';
$domdoc = new DoMDocument();
$domdoc->loadXML($xmldoc);
$xpath = new DOMXPath($domdoc);
$rootNodeListParent = $xpath->query("//root");
$rootNodeParent = $rootNodeListParent[0];
echo "The Name of the parent node is " . $rootNodeParent->nodeName. " Its value is " . $rootNodeParent->nodeValue . "<br>";
$queryNodeList = $xpath->query("//space");
$nodeSpace = $queryNodeList[0];
echo "The child node is " . $nodeSpace->nodeName. "Its value is " . $nodeSpace->nodeValue; //spacevalue ssddd
}