<?php
/ Creates an instance of the DOMImplementation class
$imp = new DOMImplementation;
/ Creates a DOMDocumentType instance
$dtd = $imp->createDocumentType('graph', '', 'graph.dtd');
/ Creates a DOMDocument instance
$dom = $imp->createDocument("", "", $dtd);
/ Set other properties
$dom->encoding = 'UTF-8';
$dom->standalone = false;
/ Create an empty element
$element = $dom->createElement('graph');
/ Append the element
$dom->appendChild($element);
/ Retrieve and print the document
echo $dom->saveXML();
?>
The above example will output:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE graph SYSTEM "graph.dtd">
<graph/>