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验证

通过浏览器默认行为或自定义样式和 JavaScript，通过 HTML5 表单验证向用户提供有价值的、可操作的反馈。

目录

我们知道目前客户端的自定义验证样式和提示信息不可访问，因为它们未向辅助技术开放。在我们寻找解决方案的同时，我们建议使用服务器端选项或默认的浏览器验证方法。

怎么运行的

🌐 How it works

以下是 Bootstrap 中表单验证的工作原理：

🌐 Here’s how form validation works with Bootstrap:

  • HTML 表单验证是通过 CSS 的两个伪类 :invalid 和 :valid 实现的。它适用于 <input>、<select> 和 <textarea> 元素。
  • Bootstrap 将 :invalid 和 :valid 样式限定在父类 .was-validated 上，通常应用于 <form>。否则，任何没有值的必填字段在页面加载时都会显示为无效。通过这种方式，你可以选择何时激活它们（通常是在尝试提交表单之后）。
  • 要重置表单的外观（例如，在使用 Ajax 的动态表单提交的情况下），在提交后再次从 <form> 中移除 .was-validated 类。
  • 作为备用，可以使用 .is-invalid 和 .is-valid 类来替代伪类进行 服务器端验证。它们不需要 .was-validated 父类。
  • 由于 CSS 的工作方式的限制，我们目前无法在没有自定义 JavaScript 帮助的情况下，对出现在 DOM 中表单控件之前的 <label> 应用样式。
  • 所有现代浏览器都支持 约束验证 API，这是一系列用于验证表单控件的 JavaScript 方法。
  • 反馈消息可能使用浏览器默认设置（每个浏览器不同，并且无法通过 CSS 样式化）或我们自定义的反馈样式，使用额外的 HTML 和 CSS。
  • 你可以在 JavaScript 中使用 setCustomValidity 提供自定义有效性消息。

考虑到这一点，请考虑以下有关我们的自定义表单验证样式、可选服务器端类和浏览器默认值的演示。

🌐 With that in mind, consider the following demos for our custom form validation styles, optional server-side classes, and browser defaults.

定制款式

🌐 Custom styles

对于自定义的 Bootstrap 表单验证消息，你需要在你的 <form> 上添加 novalidate 布尔属性。这会禁用浏览器默认的反馈提示，但仍然可以访问 JavaScript 中的表单验证 API。尝试提交下面的表单；我们的 JavaScript 会拦截提交按钮并将反馈传递给你。在尝试提交时，你将看到 :invalid 和 :valid 样式应用到你的表单控件上。

🌐 For custom Bootstrap form validation messages, you’ll need to add the novalidate boolean attribute to your <form>. This disables the browser default feedback tooltips, but still provides access to the form validation APIs in JavaScript. Try to submit the form below; our JavaScript will intercept the submit button and relay feedback to you. When attempting to submit, you’ll see the :invalid and :valid styles applied to your form controls.

自定义反馈样式应用自定义颜色、边框、焦点样式和背景图标，以更好地传达反馈。<select> 的背景图标仅适用于 .form-select，而不适用于 .form-control。

🌐 Custom feedback styles apply custom colors, borders, focus styles, and background icons to better communicate feedback. Background icons for <select>s are only available with .form-select, and not .form-control.

Looks good!
Looks good!
@
Please choose a username.
Please provide a valid city.
Please select a valid state.
Please provide a valid zip.
You must agree before submitting.
html 
<form class="row g-3 needs-validation" novalidate>
  <div class="col-md-4">
    <label for="validationCustom01" class="form-label">First name</label>
    <input type="text" class="form-control" id="validationCustom01" value="Mark" required>
    <div class="valid-feedback">
      Looks good!
    </div>
  </div>
  <div class="col-md-4">
    <label for="validationCustom02" class="form-label">Last name</label>
    <input type="text" class="form-control" id="validationCustom02" value="Otto" required>
    <div class="valid-feedback">
      Looks good!
    </div>
  </div>
  <div class="col-md-4">
    <label for="validationCustomUsername" class="form-label">Username</label>
    <div class="input-group has-validation">
      <span class="input-group-text" id="inputGroupPrepend">@</span>
      <input type="text" class="form-control" id="validationCustomUsername" aria-describedby="inputGroupPrepend" required>
      <div class="invalid-feedback">
        Please choose a username.
      </div>
    </div>
  </div>
  <div class="col-md-6">
    <label for="validationCustom03" class="form-label">City</label>
    <input type="text" class="form-control" id="validationCustom03" required>
    <div class="invalid-feedback">
      Please provide a valid city.
    </div>
  </div>
  <div class="col-md-3">
    <label for="validationCustom04" class="form-label">State</label>
    <select class="form-select" id="validationCustom04" required>
      <option selected disabled value="">Choose...</option>
      <option>...</option>
    </select>
    <div class="invalid-feedback">
      Please select a valid state.
    </div>
  </div>
  <div class="col-md-3">
    <label for="validationCustom05" class="form-label">Zip</label>
    <input type="text" class="form-control" id="validationCustom05" required>
    <div class="invalid-feedback">
      Please provide a valid zip.
    </div>
  </div>
  <div class="col-12">
    <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>
  <div class="col-12">
    <button class="btn btn-primary" type="submit">Submit form</button>
  </div>
</form>
// Example starter JavaScript for disabling form submissions if there are invalid fields
(() => {
  'use strict'

  // Fetch all the forms we want to apply custom Bootstrap validation styles to
  const forms = document.querySelectorAll('.needs-validation')

  // Loop over them and prevent submission
  Array.from(forms).forEach(form => {
    form.addEventListener('submit', event => {
      if (!form.checkValidity()) {
        event.preventDefault()
        event.stopPropagation()
      }

      form.classList.add('was-validated')
    }, false)
  })
})()

浏览器默认设置

🌐 Browser defaults

对自定义验证反馈消息或编写 JavaScript 来更改表单行为不感兴趣？没关系，你可以使用浏览器默认设置。试着提交下面的表单。根据你的浏览器和操作系统，你会看到略有不同风格的反馈。

🌐 Not interested in custom validation feedback messages or writing JavaScript to change form behaviors? All good, you can use the browser defaults. Try submitting the form below. Depending on your browser and OS, you’ll see a slightly different style of feedback.

虽然这些反馈样式无法使用 CSS 设置样式，但你仍然可以通过 JavaScript 自定义反馈文本。

🌐 While these feedback styles cannot be styled with CSS, you can still customize the feedback text through JavaScript.

@
html 
<form class="row g-3">
  <div class="col-md-4">
    <label for="validationDefault01" class="form-label">First name</label>
    <input type="text" class="form-control" id="validationDefault01" value="Mark" required>
  </div>
  <div class="col-md-4">
    <label for="validationDefault02" class="form-label">Last name</label>
    <input type="text" class="form-control" id="validationDefault02" value="Otto" required>
  </div>
  <div class="col-md-4">
    <label for="validationDefaultUsername" class="form-label">Username</label>
    <div class="input-group">
      <span class="input-group-text" id="inputGroupPrepend2">@</span>
      <input type="text" class="form-control" id="validationDefaultUsername" aria-describedby="inputGroupPrepend2" required>
    </div>
  </div>
  <div class="col-md-6">
    <label for="validationDefault03" class="form-label">City</label>
    <input type="text" class="form-control" id="validationDefault03" required>
  </div>
  <div class="col-md-3">
    <label for="validationDefault04" class="form-label">State</label>
    <select class="form-select" id="validationDefault04" required>
      <option selected disabled value="">Choose...</option>
      <option>...</option>
    </select>
  </div>
  <div class="col-md-3">
    <label for="validationDefault05" class="form-label">Zip</label>
    <input type="text" class="form-control" id="validationDefault05" required>
  </div>
  <div class="col-12">
    <div class="form-check">
      <input class="form-check-input" type="checkbox" value="" id="invalidCheck2" required>
      <label class="form-check-label" for="invalidCheck2">
        Agree to terms and conditions
      </label>
    </div>
  </div>
  <div class="col-12">
    <button class="btn btn-primary" type="submit">Submit form</button>
  </div>
</form>

服务器端

🌐 Server-side

我们建议使用客户端验证，但如果你需要服务器端验证，你可以使用 .is-invalid 和 .is-valid 来标记无效和有效的表单字段。请注意，这些类也支持 .invalid-feedback。

🌐 We recommend using client-side validation, but in case you require server-side validation, you can indicate invalid and valid form fields with .is-invalid and .is-valid. Note that .invalid-feedback is also supported with these classes.

对于无效的字段，确保将无效的反馈/错误消息与相关的表单字段关联使用 aria-describedby（请注意，该属性允许引用多个 id，以防该字段已经指向其他表单文本）。

🌐 For invalid fields, ensure that the invalid feedback/error message is associated with the relevant form field using aria-describedby (noting that this attribute allows more than one id to be referenced, in case the field already points to additional form text).

要修复 border radius 的问题，输入组需要额外的 .has-validation 类。

🌐 To fix issues with border radius, input groups require an additional .has-validation class.

Looks good!
Looks good!
@
Please choose a username.
Please provide a valid city.
Please select a valid state.
Please provide a valid zip.
You must agree before submitting.
html 
<form class="row g-3">
  <div class="col-md-4">
    <label for="validationServer01" class="form-label">First name</label>
    <input type="text" class="form-control is-valid" id="validationServer01" value="Mark" required>
    <div class="valid-feedback">
      Looks good!
    </div>
  </div>
  <div class="col-md-4">
    <label for="validationServer02" class="form-label">Last name</label>
    <input type="text" class="form-control is-valid" id="validationServer02" value="Otto" required>
    <div class="valid-feedback">
      Looks good!
    </div>
  </div>
  <div class="col-md-4">
    <label for="validationServerUsername" class="form-label">Username</label>
    <div class="input-group has-validation">
      <span class="input-group-text" id="inputGroupPrepend3">@</span>
      <input type="text" class="form-control is-invalid" id="validationServerUsername" aria-describedby="inputGroupPrepend3 validationServerUsernameFeedback" required>
      <div id="validationServerUsernameFeedback" class="invalid-feedback">
        Please choose a username.
      </div>
    </div>
  </div>
  <div class="col-md-6">
    <label for="validationServer03" class="form-label">City</label>
    <input type="text" class="form-control is-invalid" id="validationServer03" aria-describedby="validationServer03Feedback" required>
    <div id="validationServer03Feedback" class="invalid-feedback">
      Please provide a valid city.
    </div>
  </div>
  <div class="col-md-3">
    <label for="validationServer04" class="form-label">State</label>
    <select class="form-select is-invalid" id="validationServer04" aria-describedby="validationServer04Feedback" required>
      <option selected disabled value="">Choose...</option>
      <option>...</option>
    </select>
    <div id="validationServer04Feedback" class="invalid-feedback">
      Please select a valid state.
    </div>
  </div>
  <div class="col-md-3">
    <label for="validationServer05" class="form-label">Zip</label>
    <input type="text" class="form-control is-invalid" id="validationServer05" aria-describedby="validationServer05Feedback" required>
    <div id="validationServer05Feedback" class="invalid-feedback">
      Please provide a valid zip.
    </div>
  </div>
  <div class="col-12">
    <div class="form-check">
      <input class="form-check-input is-invalid" type="checkbox" value="" id="invalidCheck3" aria-describedby="invalidCheck3Feedback" required>
      <label class="form-check-label" for="invalidCheck3">
        Agree to terms and conditions
      </label>
      <div id="invalidCheck3Feedback" class="invalid-feedback">
        You must agree before submitting.
      </div>
    </div>
  </div>
  <div class="col-12">
    <button class="btn btn-primary" type="submit">Submit form</button>
  </div>
</form>

支持的元素

🌐 Supported elements

验证样式可用于以下表单控件和组件：

🌐 Validation styles are available for the following form controls and components:

  • <input> 和 <textarea> 与 .form-control（包括输入组中最多一个 .form-control）
  • <select> 与 .form-select
  • .form-checks
Please enter a message in the textarea.
Example invalid feedback text
More example invalid feedback text
Example invalid select feedback
Example invalid form file feedback
html 
<form class="was-validated">
  <div class="mb-3">
    <label for="validationTextarea" class="form-label">Textarea</label>
    <textarea class="form-control" id="validationTextarea" placeholder="Required example textarea" required></textarea>
    <div class="invalid-feedback">
      Please enter a message in the textarea.
    </div>
  </div>

  <div class="form-check mb-3">
    <input type="checkbox" class="form-check-input" id="validationFormCheck1" required>
    <label class="form-check-label" for="validationFormCheck1">Check this checkbox</label>
    <div class="invalid-feedback">Example invalid feedback text</div>
  </div>

  <div class="form-check">
    <input type="radio" class="form-check-input" id="validationFormCheck2" name="radio-stacked" required>
    <label class="form-check-label" for="validationFormCheck2">Toggle this radio</label>
  </div>
  <div class="form-check mb-3">
    <input type="radio" class="form-check-input" id="validationFormCheck3" name="radio-stacked" required>
    <label class="form-check-label" for="validationFormCheck3">Or toggle this other radio</label>
    <div class="invalid-feedback">More example invalid feedback text</div>
  </div>

  <div class="mb-3">
    <select class="form-select" required aria-label="select example">
      <option value="">Open this select menu</option>
      <option value="1">One</option>
      <option value="2">Two</option>
      <option value="3">Three</option>
    </select>
    <div class="invalid-feedback">Example invalid select feedback</div>
  </div>

  <div class="mb-3">
    <input type="file" class="form-control" aria-label="file example" required>
    <div class="invalid-feedback">Example invalid form file feedback</div>
  </div>

  <div class="mb-3">
    <button class="btn btn-primary" type="submit" disabled>Submit form</button>
  </div>
</form>

工具提示

🌐 Tooltips

如果你的表单布局允许，你可以将 .{valid|invalid}-feedback 类替换为 .{valid|invalid}-tooltip 类，以在样式化的工具提示中显示验证反馈。确保有一个带有 position: relative 的父元素以用于工具提示定位。在下面的示例中，我们的列类已经具备此功能，但你的项目可能需要其他设置。

🌐 If your form layout allows it, you can swap the .{valid|invalid}-feedback classes for .{valid|invalid}-tooltip classes to display validation feedback in a styled tooltip. Be sure to have a parent with position: relative on it for tooltip positioning. In the example below, our column classes have this already, but your project may require an alternative setup.

Looks good!
Looks good!
@
Please choose a unique and valid username.
Please provide a valid city.
Please select a valid state.
Please provide a valid zip.
html 
<form class="row g-3 needs-validation" novalidate>
  <div class="col-md-4 position-relative">
    <label for="validationTooltip01" class="form-label">First name</label>
    <input type="text" class="form-control" id="validationTooltip01" value="Mark" required>
    <div class="valid-tooltip">
      Looks good!
    </div>
  </div>
  <div class="col-md-4 position-relative">
    <label for="validationTooltip02" class="form-label">Last name</label>
    <input type="text" class="form-control" id="validationTooltip02" value="Otto" required>
    <div class="valid-tooltip">
      Looks good!
    </div>
  </div>
  <div class="col-md-4 position-relative">
    <label for="validationTooltipUsername" class="form-label">Username</label>
    <div class="input-group has-validation">
      <span class="input-group-text" id="validationTooltipUsernamePrepend">@</span>
      <input type="text" class="form-control" id="validationTooltipUsername" aria-describedby="validationTooltipUsernamePrepend" required>
      <div class="invalid-tooltip">
        Please choose a unique and valid username.
      </div>
    </div>
  </div>
  <div class="col-md-6 position-relative">
    <label for="validationTooltip03" class="form-label">City</label>
    <input type="text" class="form-control" id="validationTooltip03" required>
    <div class="invalid-tooltip">
      Please provide a valid city.
    </div>
  </div>
  <div class="col-md-3 position-relative">
    <label for="validationTooltip04" class="form-label">State</label>
    <select class="form-select" id="validationTooltip04" required>
      <option selected disabled value="">Choose...</option>
      <option>...</option>
    </select>
    <div class="invalid-tooltip">
      Please select a valid state.
    </div>
  </div>
  <div class="col-md-3 position-relative">
    <label for="validationTooltip05" class="form-label">Zip</label>
    <input type="text" class="form-control" id="validationTooltip05" required>
    <div class="invalid-tooltip">
      Please provide a valid zip.
    </div>
  </div>
  <div class="col-12">
    <button class="btn btn-primary" type="submit">Submit form</button>
  </div>
</form>

CSS

变量

🌐 Variables

Added in v5.3.0

作为 Bootstrap 不断发展的 CSS 变量方法的一部分，表单现在使用本地 CSS 变量进行验证，以增强实时自定义功能。CSS 变量的值通过 Sass 设置，因此仍然支持 Sass 自定义。

🌐 As part of Bootstrap’s evolving CSS variables approach, forms now use local CSS variables for validation for enhanced real-time customization. Values for the CSS variables are set via Sass, so Sass customization is still supported, too.

scss/_root.scss 
--#{$prefix}form-valid-color: #{$form-valid-color};
--#{$prefix}form-valid-border-color: #{$form-valid-border-color};
--#{$prefix}form-invalid-color: #{$form-invalid-color};
--#{$prefix}form-invalid-border-color: #{$form-invalid-border-color};

这些变量也是颜色模式自适应的，这意味着它们在黑夜间模式下会改变颜色。

🌐 These variables are also color mode adaptive, meaning they change color while in dark mode.

Sass 变量

🌐 Sass variables

scss/_variables.scss 
$form-feedback-margin-top:          $form-text-margin-top;
$form-feedback-font-size:           $form-text-font-size;
$form-feedback-font-style:          $form-text-font-style;
$form-feedback-valid-color:         $success;
$form-feedback-invalid-color:       $danger;

$form-feedback-icon-valid-color:    $form-feedback-valid-color;
$form-feedback-icon-valid:          url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 8 8'><path fill='#{$form-feedback-icon-valid-color}' d='M2.3 6.73.6 4.53c-.4-1.04.46-1.4 1.1-.8l1.1 1.4 3.4-3.8c.6-.63 1.6-.27 1.2.7l-4 4.6c-.43.5-.8.4-1.1.1'/></svg>");
$form-feedback-icon-invalid-color:  $form-feedback-invalid-color;
$form-feedback-icon-invalid:        url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12' width='12' height='12' fill='none' stroke='#{$form-feedback-icon-invalid-color}'><circle cx='6' cy='6' r='4.5'/><path stroke-linejoin='round' d='M5.8 3.6h.4L6 6.5z'/><circle cx='6' cy='8.2' r='.6' fill='#{$form-feedback-icon-invalid-color}' stroke='none'/></svg>");
scss/_variables.scss 
$form-valid-color:                  $form-feedback-valid-color;
$form-valid-border-color:           $form-feedback-valid-color;
$form-invalid-color:                $form-feedback-invalid-color;
$form-invalid-border-color:         $form-feedback-invalid-color;
scss/_variables-dark.scss 
$form-valid-color-dark:             $green-300;
$form-valid-border-color-dark:      $green-300;
$form-invalid-color-dark:           $red-300;
$form-invalid-border-color-dark:    $red-300;

Sass 混入

🌐 Sass mixins

通过我们的 loop，将两个 mixin 结合起来，以生成我们的表单验证反馈样式。

🌐 Two mixins are combined, through our loop, to generate our form validation feedback styles.

scss/mixins/_forms.scss 
@mixin form-validation-state-selector($state) {
  @if ($state == "valid" or $state == "invalid") {
    .was-validated #{if(&, "&", "")}:#{$state},
    #{if(&, "&", "")}.is-#{$state} {
      @content;
    }
  } @else {
    #{if(&, "&", "")}.is-#{$state} {
      @content;
    }
  }
}

@mixin form-validation-state(
  $state,
  $color,
  $icon,
  $tooltip-color: color-contrast($color),
  $tooltip-bg-color: rgba($color, $form-feedback-tooltip-opacity),
  $focus-box-shadow: 0 0 $input-btn-focus-blur $input-focus-width rgba($color, $input-btn-focus-color-opacity),
  $border-color: $color
) {
  .#{$state}-feedback {
    display: none;
    width: 100%;
    margin-top: $form-feedback-margin-top;
    @include font-size($form-feedback-font-size);
    font-style: $form-feedback-font-style;
    color: $color;
  }

  .#{$state}-tooltip {
    position: absolute;
    top: 100%;
    z-index: 5;
    display: none;
    max-width: 100%; // Contain to parent when possible
    padding: $form-feedback-tooltip-padding-y $form-feedback-tooltip-padding-x;
    margin-top: .1rem;
    @include font-size($form-feedback-tooltip-font-size);
    line-height: $form-feedback-tooltip-line-height;
    color: $tooltip-color;
    background-color: $tooltip-bg-color;
    @include border-radius($form-feedback-tooltip-border-radius);
  }

  @include form-validation-state-selector($state) {
    ~ .#{$state}-feedback,
    ~ .#{$state}-tooltip {
      display: block;
    }
  }

  .form-control {
    @include form-validation-state-selector($state) {
      border-color: $border-color;

      @if $enable-validation-icons {
        padding-right: $input-height-inner;
        background-image: escape-svg($icon);
        background-repeat: no-repeat;
        background-position: right $input-height-inner-quarter center;
        background-size: $input-height-inner-half $input-height-inner-half;
      }

      &:focus {
        border-color: $border-color;
        @if $enable-shadows {
          @include box-shadow($input-box-shadow, $focus-box-shadow);
        } @else {
          // Avoid using mixin so we can pass custom focus shadow properly
          box-shadow: $focus-box-shadow;
        }
      }
    }
  }

  // stylelint-disable-next-line selector-no-qualifying-type
  textarea.form-control {
    @include form-validation-state-selector($state) {
      @if $enable-validation-icons {
        padding-right: $input-height-inner;
        background-position: top $input-height-inner-quarter right $input-height-inner-quarter;
      }
    }
  }

  .form-select {
    @include form-validation-state-selector($state) {
      border-color: $border-color;

      @if $enable-validation-icons {
        &:not([multiple]):not([size]),
        &:not([multiple])[size="1"] {
          --#{$prefix}form-select-bg-icon: #{escape-svg($icon)};
          padding-right: $form-select-feedback-icon-padding-end;
          background-position: $form-select-bg-position, $form-select-feedback-icon-position;
          background-size: $form-select-bg-size, $form-select-feedback-icon-size;
        }
      }

      &:focus {
        border-color: $border-color;
        @if $enable-shadows {
          @include box-shadow($form-select-box-shadow, $focus-box-shadow);
        } @else {
          // Avoid using mixin so we can pass custom focus shadow properly
          box-shadow: $focus-box-shadow;
        }
      }
    }
  }

  .form-control-color {
    @include form-validation-state-selector($state) {
      @if $enable-validation-icons {
        width: add($form-color-width, $input-height-inner);
      }
    }
  }

  .form-check-input {
    @include form-validation-state-selector($state) {
      border-color: $border-color;

      &:checked {
        background-color: $color;
      }

      &:focus {
        box-shadow: $focus-box-shadow;
      }

      ~ .form-check-label {
        color: $color;
      }
    }
  }
  .form-check-inline .form-check-input {
    ~ .#{$state}-feedback {
      margin-left: .5em;
    }
  }

  .input-group {
    > .form-control:not(:focus),
    > .form-select:not(:focus),
    > .form-floating:not(:focus-within) {
      @include form-validation-state-selector($state) {
        @if $state == "valid" {
          z-index: 3;
        } @else if $state == "invalid" {
          z-index: 4;
        }
      }
    }
  }
}

Sass 映射

🌐 Sass maps

这是来自 _variables.scss 的验证 Sass 映射。可以覆盖或扩展它以生成不同或额外的状态。

🌐 This is the validation Sass map from _variables.scss. Override or extend this to generate different or additional states.

scss/_variables.scss 
$form-validation-states: (
  "valid": (
    "color": var(--#{$prefix}form-valid-color),
    "icon": $form-feedback-icon-valid,
    "tooltip-color": #fff,
    "tooltip-bg-color": var(--#{$prefix}success),
    "focus-box-shadow": 0 0 $input-btn-focus-blur $input-focus-width rgba(var(--#{$prefix}success-rgb), $input-btn-focus-color-opacity),
    "border-color": var(--#{$prefix}form-valid-border-color),
  ),
  "invalid": (
    "color": var(--#{$prefix}form-invalid-color),
    "icon": $form-feedback-icon-invalid,
    "tooltip-color": #fff,
    "tooltip-bg-color": var(--#{$prefix}danger),
    "focus-box-shadow": 0 0 $input-btn-focus-blur $input-focus-width rgba(var(--#{$prefix}danger-rgb), $input-btn-focus-color-opacity),
    "border-color": var(--#{$prefix}form-invalid-border-color),
  )
);

$form-validation-states 的地图可以包含三个可选参数，以覆盖工具提示和焦点样式。

🌐 Maps of $form-validation-states can contain three optional parameters to override tooltips and focus styles.

Sass 循环

🌐 Sass loops

用于迭代 $form-validation-states 映射的值以生成我们的验证样式。对上述 Sass 映射的任何修改都将通过此循环反映在编译后的 CSS 中。

🌐 Used to iterate over $form-validation-states map values to generate our validation styles. Any modifications to the above Sass map will be reflected in your compiled CSS via this loop.

scss/forms/_validation.scss 
@each $state, $data in $form-validation-states {
  @include form-validation-state($state, $data...);
}

定制

🌐 Customizing

验证状态可以通过 Sass 使用 $form-validation-states 映射进行自定义。该 Sass 映射位于我们的 _variables.scss 文件中，它用于生成默认的 valid/invalid 验证状态。包括一个嵌套映射，用于自定义每个状态的颜色、图标、提示颜色和焦点阴影。虽然浏览器不支持其他状态，但使用自定义样式的用户可以轻松添加更复杂的表单反馈。

🌐 Validation states can be customized via Sass with the $form-validation-states map. Located in our _variables.scss file, this Sass map is how we generate the default valid/invalid validation states. Included is a nested map for customizing each state’s color, icon, tooltip color, and focus shadow. While no other states are supported by browsers, those using custom styles can easily add more complex form feedback.