<?php
$doc = new DOMDocument;
$doc->load('book.xml');
$book = $doc->documentElement;
// we retrieve the chapter and remove it from the book
$chapter = $book->getElementsByTagName('chapter')->item(0);
$oldchapter = $book->removeChild($chapter);
echo $doc->saveXML();
?>
The above example will output:
<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<book id="listing">
<title>My lists</title>
</book>