tepTest.value = "12:00";
  _StepTest.step = "1";
  _StepTest.stepUp();
  assert_in_array(
    _StepTest.value,
    [
      "12:00:01",
      "12:00:01.0",
      "12:00:01.00",
      "12:00:01.000"],
    "a valid time string representing 1 second after noon");
} , "stepUp on step value second ");
test(function(){
  _StepTest.value = "12:00";
  _StepTest.step = "1";
  _StepTest.stepDown();
  assert_in_array(
    _StepTest.value,
    [
      "11:59:59",
      "11:59:59.0",
      "11:59:59.00",
      "11:59:59.