1. DomName('Element.getAttributeNS')
  2. DocsEditable()
  3. Experimental()
String getAttributeNS(String namespaceURI, String localName)

Source 

@DomName('Element.getAttributeNS')
@DocsEditable()
@Experimental() // untriaged
String getAttributeNS(String namespaceURI, String localName) => _blink.BlinkElement.instance.getAttributeNS_Callback_2_(this, namespaceURI, localName);