required 属性在 Chrome 中不起作用，但在 FireFox 中起作用答案

【问题标题】：The required attribute is not working in Chrome but does work in FireFoxrequired 属性在 Chrome 中不起作用，但在 FireFox 中起作用
【发布时间】：2021-03-26 17:06:51
【问题描述】：

我正在使用引导程序进行样式设置，但我没有定义任何自己的类。由于 FireFox 正在工作，我相信我使用的结构是正确的。但 Chrome 并不高兴，我对两者之间的细微差别了解得不够多，无法追踪。 “状态”下拉菜单的必需属性在两者中都不起作用，但我认为这是另一个问题。

我遇到了一篇文章，描述了当应用程序 url 为 ssl 时，Chrome 如何不会加载非 ssl 脚本，但这不应该适用，因为我正在使用 ng serve 并且我的 url 不安全。否则，所有与 required 属性相关的文章不起作用都与 FireFix 上的故障有关，这与我遇到的情况相反。

FireFox: 86.0.1 (64-bit)
Chrome:  89.0.4389.90 (Official Build) (64-bit)

来自组件 html

<div class="row">
  <div class="col-md-5 mb-3">
    <label for="{{idPrefix}}City">City</label>
    <input type="text" class="form-control" id="{{idPrefix}}City" placeholder="" required [(ngModel)]="model.City">
  </div>
  <div class="col-md-4 mb-3">
    <label for="{{idPrefix}}state">State</label>
    <select class="custom-select d-block w-100" id="{{idPrefix}}state" required [(ngModel)]="model.State">
      <option value="">Choose...</option>
      <option *ngFor="let State of StateArray" value="{{State.abbreviation}}">{{State.name}}</option>
    </select>
  </div>
  <div class="col-md-3 mb-3">
    <label for="{{idPrefix}}zip">Zip</label>
    <input type="text" class="form-control" id="{{idPrefix}}zip" placeholder="" required [(ngModel)]="model.Zip">
  </div>
</div>

index.html

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css">

【问题讨论】：

该属性有效，如果您尝试发布表单，它会告诉您缺少字段。 Firefox 中的红色框阴影是一种用户代理样式，而 Chrome 则没有。如果你想要它无处不在，你可以用:invalid 伪类编写你自己的。

标签： html google-chrome firefox required-field

【解决方案1】：

通常 chrome 不会为无效输入创建此红色边框。您可以手动添加一些 css 来创建该边框：

input:required {
  border-color: #800000;
  border-width: 3px;
}

input:invalid {
  background-color: #ffdddd;
}

input:valid {
  background-color: #ddffdd;
}

但老实说，我真的不知道你会如何单独使用 bootsrap 来做到这一点。

【讨论】：

【解决方案2】：

检查下面的代码，它适用于所有浏览器

    <!doctype html>
<html lang="en">
<head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">

    <title>Test</title>
</head>
<body>
<form class="needs-validation" novalidate>
  <div class="form-row">
    <div class="col-md-4 mb-3">
      <label for="validationCustom01">First name</label>
      <input type="text" class="form-control" id="validationCustom01" placeholder="First name" value="Mark" required>
      <div class="valid-feedback">
        Looks good!
      </div>
    </div>
    <div class="col-md-4 mb-3">
      <label for="validationCustom02">Last name</label>
      <input type="text" class="form-control" id="validationCustom02" placeholder="Last name" value="Otto" required>
      <div class="valid-feedback">
        Looks good!
      </div>
    </div>
    <div class="col-md-4 mb-3">
      <label for="validationCustomUsername">Username</label>
      <div class="input-group">
        <div class="input-group-prepend">
          <span class="input-group-text" id="inputGroupPrepend">@</span>
        </div>
        <input type="text" class="form-control" id="validationCustomUsername" placeholder="Username" aria-describedby="inputGroupPrepend" required>
        <div class="invalid-feedback">
          Please choose a username.
        </div>
      </div>
    </div>
  </div>
  <div class="form-row">
    <div class="col-md-6 mb-3">
      <label for="validationCustom03">City</label>
      <input type="text" class="form-control" id="validationCustom03" placeholder="City" required>
      <div class="invalid-feedback">
        Please provide a valid city.
      </div>
    </div>
    <div class="col-md-3 mb-3">
      <label for="validationCustom04">State</label>
      <input type="text" class="form-control" id="validationCustom04" placeholder="State" required>
      <div class="invalid-feedback">
        Please provide a valid state.
      </div>
    </div>
    <div class="col-md-3 mb-3">
      <label for="validationCustom05">Zip</label>
      <input type="text" class="form-control" id="validationCustom05" placeholder="Zip" required>
      <div class="invalid-feedback">
        Please provide a valid zip.
      </div>
    </div>
  </div>
  <div class="form-group">
    <div class="form-check">
      <input class="form-check-input" type="checkbox" value="" id="invalidCheck" required>
      <label class="form-check-label" for="invalidCheck">
        Agree to terms and conditions
      </label>
      <div class="invalid-feedback">
        You must agree before submitting.
      </div>
    </div>
  </div>
  <button class="btn btn-primary" type="submit">Submit form</button>
</form>

<script>
// Example starter JavaScript for disabling form submissions if there are invalid fields
(function() {
  'use strict';
  window.addEventListener('load', function() {
    // Fetch all the forms we want to apply custom Bootstrap validation styles to
    var forms = document.getElementsByClassName('needs-validation');
    // Loop over them and prevent submission
    var validation = Array.prototype.filter.call(forms, function(form) {
      form.addEventListener('submit', function(event) {
        if (form.checkValidity() === false) {
          event.preventDefault();
          event.stopPropagation();
        }
        form.classList.add('was-validated');
      }, false);
    });
  }, false);
})();
</script>


</body>

    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
</body>
</html>

您可以参考以下文档：https://getbootstrap.com/docs/4.0/components/forms/?#validation

【讨论】：