/*<?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <!-- css Style definition, no dot. Such as: name{color:red;} -->
<?xml-stylesheet type="text/css" href="css.css"?>
<!--  The introduction of dtd Document definition file   (root element: class) <!DOCTYPE  The class  SYSTEM "class.dtd" /> -->
<!-- <!DOCTYPE  The class [
<!ELEMENT  The class  ( students +)>
<!ELEMENT  students  ( The name , age , introduce )>
<!ELEMENT  The name  (#PCDATA)>
<!ELEMENT  age  (#PCDATA)>
<!ELEMENT  introduce  (#PCDATA)>
] /> -->
< The class >
< students  number="101">
< The name > The Monkey King </ The name >
< The name > Sun walkers </ The name >
< age >123</ age >
< introduce ><![CDATA[&*$% Special string ^&#$&]]></ introduce >
</ students >
< students  number="10&quot;2">
< The name > Bones jing </ The name >
< age >140</ age >
< introduce > Introduce the content </ introduce >
</ students >
</ The class >
*/
$xmldoc = new DOMDocument('1.0', 'UTF-8');
$xmldoc->load('datas.xml');
$itemsNodeList = $xmldoc->getElementsbyTagName(' students ');
$itemElement = $itemsNodeList->item(0);// Get the first 1 A complete student information node
$itemChildsNodeList = $itemElement->getElementsbyTagName(' The name ');// Gets the child node "name," which may have multiple names
$itemChildNode = $itemChildsNodeList->item(0);// Get the first 1 Name node
echo $itemChildNode->nodeValue;// Output node value
// Encapsulated as a function
$nodeArr = array(' The name ', ' age ', ' introduce ');
function getNodeVal($xmldoc, $itemsName, $nodeArr){
    $items = $xmldoc->getElementsByTagName($itemsName);
     for($i=0; $i < $items->length; $i++){
        $item = $items->item($i);
        foreach($nodeArr as $node){
            $data[$i][] = $item->getElementsByTagName($node)->item(0)->nodeValue;
        }
    }
    return $data;
}
$data = getNodeVal($xmldoc, ' students ', $nodeArr);
print_r($data);

// Add a node
$xmldoc = new DOMDocument('1.0', 'UTF-8');
$xmldoc->load('datas.xml');
$items = $xmldoc->getElementsByTagName(' The class ')->item(0);// The root node
$student =  $xmldoc->createElement(' students ');// create 1 A new student node
$stu_name = $xmldoc->createElement(' The name ',' zhang 3');
$stu_age = $xmldoc->createElement(' age ','15');
$stu_intro = $xmldoc->createElement(' introduce ',' Strong practical ability and stable performance ');
$items->appendChild($student);
$student->appendChild($stu_name);
$student->appendChild($stu_age);
$student->appendChild($stu_intro);
$bytes = $xmldoc->save('datas.xml');
echo ($bytes)? " Written into the : $bytes  byte " : ' Save failed ';
// Remove nodes
$xmldoc = new DOMDocument('1.0', 'UTF-8');
$xmldoc->load('datas.xml');
$student = $xmldoc->getElementsByTagName(' students ')->item(2);// Go directly to the node you want to delete
$student->parentNode->removeChild($student);// The delete method of the parent node
$xmldoc->save('datas.xml');
// Modify node values
$student = $xmldoc->getElementsByTagName(' students ')->item(2);
$student->getElementsByTagName(' age ')->item(0)->nodeValue += 10;
$student->setAttribute('id', '110');
$xmldoc->save('datas.xml');
// application  Xpath  Find nodes
$xml = new DOMDocument('1.0', 'UTF-8');
$xml->load('dat.xml');
$xpath = new DOMXPath($xml);
$nodeList = $xpath->query('/aaa/bbb/ddd/fff');
echo $nodeList->item(0)->nodeValue;
//SimpleXML  Class action  xml
/*
<?xml version="1.0" encoding="UTF-8"?>
<books>
<book house=" Tsinghua university press ">
<code>1001</code>
<price>200 yuan </price>
<author> daming </author>
<title> Draco 8 The ministry of </title>
</book>
<book house=" Peking University publishing ">
<code>1002</code>
<price>321 yuan </price>
<author> zhang 3</author>
<title> The Legendary Swordsman </title>
</book>
<book house=" people   People published ">
<code>1004</code>
<price>182 yuan </price>
<author> li 4</author>
<title> The reader </title>
</book>
</books>
*/
$xml = simplexml_load_file('books.xml');
$books = $xml->book;
echo $books[1]->title . $books[1]['house'];// Direct pointing control 2 This book
foreach($xml as $item){
    echo $item->title,' ',$item['house'],'<br/>';
}