addChild and attribute with simpleXml

<?php 
header('Content-type: text/xml');
 
// first <winner id="1" /> node
$xml = 
'<win visit="0">
    <winner id="1" />
</win>'; 
$xml = simplexml_load_string($xml); 
 
// second node
$newNode = $xml->addChild("winner");
$newNode->addAttribute("id","2");
 
// three node
$newNode = $xml->addChild("winner");
$newNode->addAttribute("id","3");
 
echo $xml->asXML();
?>
 
// RESULT
<win visit="0">
    <winner id="1"/>
    <winner id="2"/>
    <winner id="3"/>
</win>