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# DOMDocument::registerNodeClass

(PHP 5 >= 5.2.0)

DOMDocument::registerNodeClass — Register extended class used to create base node type

### Description

public bool DOMDocument::registerNodeClass ( string `$baseclass` , string `$extendedclass` )

This method allows you to register your own extended DOM class to be used afterward by the PHP DOM extension.

This method is not part of the DOM standard.

### Parameters

`baseclass`

  The DOM class that you want to extend. You can find a list of these classes in the chapter introduction.

`extendedclass`

  Your extended class name. If `NULL` is provided, any previously registered class extending `baseclass` will be removed.

### Return Values

Returns `TRUE` on success or `FALSE` on failure.

### Changelog

Version | Description
--- | ---
5.2.2 | Prior to 5.2.2, a previously registered `extendedclass` had to be unregistered before being able to register a new class extending the same `baseclass`.

### Examples

Example #1 Adding a new method to DOMElement to ease our code

`<?php
class myElement extends DOMElement {
function appendElement($name) {
return $this->appendChild(new myElement($name));
}
}
class myDocument extends DOMDocument {
function setRoot($name) {
return $this->appendChild(new myElement($name));
}
}
$doc = new myDocument();
$doc->registerNodeClass('DOMElement', 'myElement');
// From now on, adding an element to another costs only one method call !
$root = $doc->setRoot('root');
$child = $root->appendElement('child');
$child->setAttribute('foo', 'bar');
echo $doc->saveXML();
?>`

The above example will output:

    <?xml version="1.0"?>
    <root><child foo="bar"/></root>

Example #2 Retrieving elements as custom class

`<?php
class myElement extends DOMElement {
public function __toString() {
return $this->nodeValue;
}
}
$doc = new DOMDocument;
$doc->loadXML("<root><element><child>text in child</child></element></root>");
$doc->registerNodeClass("DOMElement", "myElement");
$element = $doc->getElementsByTagName("child")->item(0);
var_dump(get_class($element));
// And take advantage of the __toString method..
echo $element;
?>`

The above example will output:

    string(9) "myElement"
    text in child

Example #3 Retrieving owner document

When instantiating a custom DOMDocument the ownerDocument property will refer to the instantiated class, meaning there is no need (and in fact not possible) to use DOMDocument::registerNodeClass() with DOMDocument

`<?php
class myDOMDocument extends DOMDocument {
}
class myOtherDOMDocument extends DOMDocument {
}
// Create myDOMDocument with some XML
$doc = new myDOMDocument;
$doc->loadXML("<root><element><child>text in child</child></element></root>");
$child = $doc->getElementsByTagName("child")->item(0);
// The current owner of the node is myDOMDocument
var_dump(get_class($child->ownerDocument));
// Import a node from myDOMDocument
$newdoc = new myOtherDOMDocument;
$child = $newdoc->importNode($child);
// The new owner of the node has changed to myOtherDOMDocument
var_dump(get_class($child->ownerDocument));
?>`

The above example will output:

    string(13) "myDOMDocument"
    string(18) "myOtherDOMDocument"

DOMDocument::normalizeDocument
DOMDocument::relaxNGValidate
DOMDocument
PHP Manual