if (desc == "HTML document") {
          doc = document;
        } else if (desc == "XML document") {
          doc = xmlIframe.contentDocument;
          // Make sure we're testing the right document
          assert_equals(doc.documentElement.textContent, "Dummy XML document");
        } else if (desc == "XHTML document") {
          doc = xhtmlIframe.contentDocument;
          assert_equals(doc.documentElement.textContent, "Dummy XHTML document");
        }
        var namespace = t[0], qualifiedName = t