# File lib/xml/dom2/element.rb, line 452
      def setAttributeNS(nsuri, qname, value)
        if qname.index(':')
          prefix, localname = qname.split(':')
          raise DOMException.new(DOMException::NAMESPACE_ERR) if
            nsuri.nil? or
            (prefix == 'xml' and
             nsuri != 'http://www.w3.org/XML/1998/namespace')
        else
          raise DOMException.new(DOMException::NAMESPACE_ERR) if
            qname == 'xmlns' and
            nsuri != 'http://www.w3.org/2000/xmlns/'
        end
        attr = @ownerDocument.createAttributeNS(nsuri, qname)
        attr.appendChild(@ownerDocument.createTextNode(value))
        setAttributeNodeNS(attr)
      end