验证
通过浏览器默认行为或自定义样式和 JavaScript，使用 HTML5 表单验证向您的用户提供有价值的、可操作的反馈。
在此页
我们知道目前无法访问客户端自定义验证样式和工具提示，因为它们未暴露给辅助技术。在我们制定解决方案时，我们建议使用服务器端选项或默认浏览器验证方法。
怎么运行的
下面是表单验证如何与 Bootstrap 一起工作：
- HTML 表单验证通过 CSS 的两个伪类应用，
:invalid和:valid. 它适用于<input>、<select>和<textarea>元素。 - Bootstrap 将
:invalid和:valid样式限定为父.was-validated类，通常应用于<form>. 否则，任何没有值的必填字段在页面加载时显示为无效。这样，您可以选择何时激活它们（通常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），请在提交后从 again中删除
.was-validated该类。<form> - 作为后备，
.is-invalid可以.is-valid使用类代替伪类进行服务器端验证。他们不需要.was-validated父类。 - 由于 CSS 工作方式的限制，我们不能（目前）
<label>在没有自定义 JavaScript 帮助的情况下将样式应用于 DOM 中表单控件之前的 a 。 - 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。
- 反馈消息可能会使用浏览器默认设置（每个浏览器都不同，并且无法通过 CSS 设置样式）或我们带有额外 HTML 和 CSS 的自定义反馈样式。
setCustomValidity您可以在 JavaScript 中提供自定义有效性消息。
考虑到这一点，请考虑以下针对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。
自定义样式
对于自定义 Bootstrap 表单验证消息，您需要将novalidate布尔属性添加到您的<form>. 这将禁用浏览器默认反馈工具提示，但仍提供对 JavaScript 中的表单验证 API 的访问。尝试提交以下表格；我们的 JavaScript 将拦截提交按钮并向您传递反馈。尝试提交时，您会看到应用于表单控件的:invalid和样式。:valid
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。s 的背景图标<select>仅适用于.form-select，不适用于.form-control。
<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)
})
})()浏览器默认值
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？很好，您可以使用浏览器默认设置。尝试提交下面的表格。根据您的浏览器和操作系统，您会看到略有不同的反馈方式。
虽然无法使用 CSS 设置这些反馈样式的样式，但您仍然可以通过 JavaScript 自定义反馈文本。
<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
我们建议使用客户端验证，但如果您需要服务器端验证，您可以使用.is-invalid和指示无效和有效的表单字段.is-valid。请注意，.invalid-feedback这些类也支持。
对于无效字段，请确保无效反馈/错误消息与使用的相关表单字段相关联aria-describedby（请注意，此属性允许id引用多个，以防该字段已指向其他表单文本）。
要解决border radius的问题，输入组需要一个额外的.has-validation类。
<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
验证样式可用于以下表单控件和组件：
<input>s 和<textarea>s with.form-control（.form-control输入组中最多包括一个）<select>与.form-select.form-check秒
<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
如果您的表单布局允许，您可以将类交换.{valid|invalid}-feedback为.{valid|invalid}-tooltip类以在样式化的工具提示中显示验证反馈。一定要有一个父position: relative级用于工具提示定位。在下面的例子中，我们的列类已经有了这个，但你的项目可能需要一个替代设置。
<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>萨斯
变量
$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-.8.4-1.1.1z'/></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='#{$form-feedback-icon-invalid-color}' stroke='none'/></svg>");
混入
通过我们的循环将两个 mixin 组合在一起，以生成我们的表单验证反馈样式。
@mixin form-validation-state-selector($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;
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;
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;
}
}
}
}
}
地图
这是来自_variables.scss. 覆盖或扩展它以生成不同的或额外的状态。
$form-validation-states: (
"valid": (
"color": var(--#{$prefix}success-text),
"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}success),
),
"invalid": (
"color": var(--#{$prefix}danger-text),
"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}danger),
)
);
地图$form-validation-states可以包含三个可选参数来覆盖工具提示和焦点样式。
环形
用于迭代$form-validation-states映射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您编译的 CSS 中。
@each $state, $data in $form-validation-states {
@include form-validation-state($state, $data...);
}
客制化
可以通过带有$form-validation-states地图的 Sass 自定义验证状态。位于我们的_variables.scss文件中，这个 Sass 映射是我们生成默认valid/invalid验证状态的方式。包括一个嵌套地图，用于自定义每个状态的颜色、图标、工具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浏览器可以轻松添加更复杂的表单反馈。