helper DOMNode::insertAfter

DomNodeInsertAfter.php

<?php
/**
 * Helper function to insert node after another node.
 * 
 * @param DOMNode $newNode Node to be appended.
 * @param DOMNode $refNode Node required to have new node appended after it.
 */
function insertAfter ( $newNode, $refNode ) {
  if( $refNode->nextSibling ){
     $refNode->parentNode->insertBefore( $newNode, $refNode->nextSibling );
  } else {
     $refNode->parentNode->appendChild( $newNode );
  }
}