有没有一种方法可以覆盖来自C＃.net表单的警报？

Question

我正在尝试使用JavaScript创建有关用户将信用卡输入框留空时的警报。但是，当我测试我创建的功能时，会出现一个警报，但它不是我创建的警报。我做了一些研究，结果发现它是使用C＃.net表单时已经集成的自动警报。因此，基本上，此警报将针对每个空的输入框出现。不知道如何问这个问题，但是有没有办法我可以覆盖该警报并改用我创建的警报？如果您查看摘要，您将看到我在说什么-我创建的警报不会出现。

function validateFormOnSubmit(AddCardForm){
	reason = "";
  reason += validateCreditCardNumber(AddCardForm.cardNumber) 
  
  console.log(reason);
    if (reason.length > 0) {

        return false;
    } else {
        return false;
    }
}


function validateCreditCardNumber(cardNumber){
		var error = "";
     if (cardNumber.value.length == 0) {
        cardNumber.style.background = 'Red';
        document.getElementById('card-error').innerHTML = "The required field has not been filled in";
        var error = "1";
    } else {
        cardNumber.style.background = 'White';
        document.getElementById('card-error').innerHTML = '';
    }
    return error;
}

<form id="AddCardForm">
  <h1 style="text-align: center">Card Details</h1>

  <div class="row">
    <div class="col-xs-12">
      <div class="form-group">
        <label for="cardNumber">CARD NUMBER</label>
        <div class="input-group">
          <input type="tel" class="form-control" name="cardNumber" placeholder="Valid Card Number" autocomplete="cc-number" required autofocus id="cardNumber" />
          <span class="input-group-addon"><i class="fa fa-credit-card"></i></span>
        </div>
        <div id="card-error" class="error"></div>
      </div>
    </div>
  </div>
  <div class="row" onsubmit="return validateForm();">
    <div class="col-xs-7 col-md-7">
      <div class="form-group">
        <label for="cardExpiry"><span class="hidden-xs">EXPIRATION</span><span class="visible-xs-inline">EXP</span> DATE</label>
        <input type="tel" class="form-control" name="cardExpiry" placeholder="12 / 2016" autocomplete="cc-exp" required autofocus id="expYear" />
      </div>
    </div>
    <div class="col-xs-5 col-md-5 pull-right">
      <div class="form-group">
        <label for="cardCVC">CVC</label>
        <input type="tel" class="form-control" name="cardCVC" placeholder="CVC" autocomplete="cc-csc" required id="cvc" />
      </div>
    </div>
  </div>

  <div class="row">
    <div class="col-xs-12">
      <div class="form-group">
        <label for="couponCode">NAME ON CARD</label>
        <input type="text" class="form-control" name="couponCode" id="name" />
      </div>
      <div id="name-error" class="error"></div>
    </div>
  </div>
  <div class="row">
    <div class="col-xs-12">
      <div class="form-group">
        <label for="couponCode">STREET ADDRESS</label>
        <input type="text" class="form-control" name="couponCode" id="streetAddress" />
      </div>
    </div>
  </div>
  <div class="row">
    <div class="col-xs-7 col-md-7">
      <div>
        <label for="couponCode">COUNTRY</label>
        <input type="text" class="form-control" name="COUNTY" value="US" readonly />
      </div>
    </div>

    <div class="col-xs-5 col-md-5 pull-right">
      <div class="form-group">
        <label for="couponCode">CITY</label>
        <input type="text" class="form-control" name="CITY" id="city" />
      </div>
    </div>
  </div>

  <div class="row">
    <div class="col-xs-7 col-md-7">
      <div>
        <label for="couponCode">REGION</label>
        <div class="form-group">
          <div class="col-xs-7">
            <select class="form-control" id="state" name="state">
              <option value="" selected>N/A</option>
              <option value="AK">Alaska</option>
              <option value="AL">Alabama</option>
              <option value="AR">Arkansas</option>
              <option value="AZ">Arizona</option>
              <option value="CA">California</option>
              <option value="CO">Colorado</option>
              <option value="CT">Connecticut</option>
              <option value="DC">District of Columbia</option>
              <option value="DE">Delaware</option>
              <option value="FL">Florida</option>
              <option value="GA">Georgia</option>
              <option value="HI">Hawaii</option>
              <option value="IA">Iowa</option>
              <option value="ID">Idaho</option>
              <option value="IL">Illinois</option>
              <option value="IN">Indiana</option>
              <option value="KS">Kansas</option>
              <option value="KY">Kentucky</option>
              <option value="LA">Louisiana</option>
              <option value="MA">Massachusetts</option>
              <option value="MD">Maryland</option>
              <option value="ME">Maine</option>
              <option value="MI">Michigan</option>
              <option value="MN">Minnesota</option>
              <option value="MO">Missouri</option>
              <option value="MS">Mississippi</option>
              <option value="MT">Montana</option>
              <option value="NC">North Carolina</option>
              <option value="ND">North Dakota</option>
              <option value="NE">Nebraska</option>
              <option value="NH">New Hampshire</option>
              <option value="NJ">New Jersey</option>
              <option value="NM">New Mexico</option>
              <option value="NV">Nevada</option>
              <option value="NY">New York</option>
              <option value="OH">Ohio</option>
              <option value="OK">Oklahoma</option>
              <option value="OR">Oregon</option>
              <option value="PA">Pennsylvania</option>
              <option value="PR">Puerto Rico</option>
              <option value="RI">Rhode Island</option>
              <option value="SC">South Carolina</option>
              <option value="SD">South Dakota</option>
              <option value="TN">Tennessee</option>
              <option value="TX">Texas</option>
              <option value="UT">Utah</option>
              <option value="VA">Virginia</option>
              <option value="VT">Vermont</option>
              <option value="WA">Washington</option>
              <option value="WI">Wisconsin</option>
              <option value="WV">West Virginia</option>
              <option value="WY">Wyoming</option>
            </select>
          </div>
        </div>
      </div>
    </div>

    <div class="col-xs-5 col-md-5 pull-right">
      <div class="form-group">
        <label for="couponCode">POSTAL CODE</label>
        <input type="text" class="form-control" name="couponCode" id="postalCode" />
      </div>
    </div>
  </div>

  <br>
  <div class="row">
    <div class="col-xs-12">
      <button class="btn btn-success btn-lg btn-block" id="createCard" type="submit">Save</button>
    </div>
  </div>
  </form