?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); 
$xml->addAttribute("type","private"); 
$xml->body->addAttribute("date","2013-01-01"); 
echo $xml->asXML(); 
?>

addAttribute( _name,value,ns_ );