(PHP 5, PHP 7)
DOMElement::getAttributeNS — Returns value of attribute
$namespaceURI
   , string $localName
   )
   Gets the value of the attribute in namespace namespaceURI 
   with local name localName for the current node. 
  
namespaceURIThe namespace URI.
localNameThe local name.
   The value of the attribute, or an empty string if no attribute with the
   given localName and namespaceURI 
   is found.