# File lib/xml/dom2/dombuilder.rb, line 248
      def startNamespaceDecl(prefix, uri)
        qname = 'xmlns'
        if prefix
          qname << ':' + prefix
        end
        attr = @document.createAttributeNS(nil, qname)
        attr.appendChild(@document.createTextNode(uri))
        attr.specified = true
        @nsdecl << attr
      end