The output should be:
<?xml version="1.0" encoding="iso-8859-1"?>
<root attr="attrvalue"/>
Creates a new DOMAttr object. This object is read only. It may be appended to a document, but additional nodes may not be appended to this node until the node is associated with a document. To create a writable node, use DOMDocument::createAttribute.
nameThe tag name of the attribute.
valueThe value of the attribute.
示例 #1 Creating a new DOMAttr object
<?php
$dom = new DOMDocument('1.0', 'iso-8859-1');
$element = $dom->appendChild(new DOMElement('root'));
$attr = $element->setAttributeNode(new DOMAttr('attr', 'attrvalue'));
echo $dom->saveXML();
?>以上示例会输出：
<?xml version="1.0" encoding="utf-8"?> <root attr="attrvalue" />