<!DOCTYPE html>
<html>
<body>

<?php
$note=<<<XML
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
XML;

$xml=new SimpleXMLElement($note);

// Add a child element to the body element
$xml->body->addChild("date","2013-01-01");

// Add a child element after the last element inside note
$footer=$xml->addChild("footer","Some footer text");

echo $xml->asXML();
?>

<p>Select View Source to see the added date element (inside the body element) and the footer element.</p>

</body>
</html>