ar element = document.createElementNS(svgNs, "feBlend");
  element.setAttribute("mode", "lighten");
  assert_equals(element.mode.baseVal, SVGFEBlendElement.SVG_FEBLEND_MODE_LIGHTEN);
  assert_equals(element.getAttribute('mode'), "lighten");

  assert_throws_js(TypeError, function() { element.mode.baseVal = 17; });
  assert_equals(element.mode.baseVal, SVGFEBlendElement.SVG_FEBLEND_MODE_LIGHTEN);
  assert_equals(element.getAttribute('mode'), "lighten");

  assert_throws_js(TypeError, function() { element.mod