NIT_TYPE_USERSPACEONUSE);
  assert_equals(maskElement.getAttribute('maskUnits'), "userSpaceOnUse");

  // maskContentUnits
  // Check initial 'maskContentUnits' value.
  assert_true(maskElement.maskContentUnits instanceof SVGAnimatedEnumeration);
  assert_equals(typeof(maskElement.maskContentUnits.baseVal), "number");
  assert_equals(maskElement.maskContentUnits.baseVal, SVGUnitTypes.SVG_UNIT_TYPE_USERSPACEONUSE);

  // Switch to 'objectBoundingBox'.
  maskElement.maskContentUnits.baseVal = SVGUnitTypes.SVG