Bootstrap - 验证
本章将讨论 Bootstrap 验证。Bootstrap 5 Validation 通过为用户提供有用的反馈来增强 HTML5 表单验证,支持默认浏览器行为、自定义样式和 JavaScript。
客户端自定义验证样式和工具提示不可访问,因为它们对辅助技术不可见。 建议使用服务器端选项或默认浏览器验证技术,同时我们正在研究解决方案。
Bootstrap 中表单验证的工作原理
CSS 中的两个伪类 :invalid 和 :valid 用于提供 HTML 表单验证。它适用于 <textarea>、<select> 和 <input> 元素。
Bootstrap 将 :invalid 和 :valid 样式应用到父级 .was-validated class 上。页面加载时没有值的字段会显示为无效状态。你可以选择何时激活它们(通常在表单提交后)。
使用 Ajax 进行动态提交后,要恢复表单的原始外观,应从 <form> 中移除 .was-validated class 以重置其外观。
对于服务器端验证,可以使用 .is-invalid 和 .is-valid class 作为后备方案,无需 .was-validated 父级 class。
目前,由于 CSS 限制,我们无法在没有自定义 JavaScript 帮助的情况下直接将样式应用到 DOM 中紧随表单控件之前的 <label> 元素。
所有现代 Web 浏览器都支持 constraint validation API,该 API 包含各种用于验证表单控件的 JavaScript 方法。
使用浏览器默认样式,或使用 HTML/CSS 创建自定义反馈样式。
使用 JavaScript 中的 setCustomValidity 方法来设置独特的有效性消息。
让我们来看一些自定义表单验证样式、可选服务器端 class 和浏览器默认的示例。
自定义样式
在 <form> 上添加 novalidate 布尔属性,以从 Bootstrap 接收自定义验证消息。
上述布尔属性会禁用浏览器默认的反馈工具提示,但 JavaScript validation APIs 仍然有效。提交此表单将触发 JavaScript 提供反馈,在表单控件上显示 :invalid 和 :valid 样式。
自定义反馈样式通过添加颜色、边框、焦点样式和背景图标来改善反馈沟通。对于 <select> 的背景图标仅适用于 .form-select,而不适用于 .form-control。
此示例演示了一个带有验证功能的 Bootstrap 表单,以确保在表单提交前必填字段被正确填写。
示例
您可以使用 Edit & Run 选项编辑并尝试运行此代码。
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap - Validation</title>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha3/dist/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha3/dist/js/bootstrap.bundle.min.js"></script>
</head>
<body>
<form class="row g-3 needs-validation" novalidate>
<div class="col-md-4">
<label for="validationCustomName" class="form-label">Full Name</label>
<input type="text" class="form-control" id="validationCustomName" value="Jhon Miller" required>
<div class="invalid-feedback">
Correct input!
</div>
</div>
<div class="col-md-4">
<label for="validationCustomEmail" class="form-label">Email Id</label>
<div class="input-group has-validation">
<input type="text" class="form-control" id="validationCustomEmail" aria-describedby="inputGroupPrepend" required>
<span class="input-group-text" id="inputGroupPrepend">@example.com</span>
<div class="invalid-feedback">
Please enter correct mail id.
</div>
</div>
</div>
<div class="col-md-4">
<label for="validationCustomPhone" class="form-label">Mobile no</label>
<input type="text" class="form-control" id="validationCustomPhone" required>
<div class="invalid-feedback">
please enter correct mobile no.
</div>
</div>
<div class="col-md-6">
<label for="validationAddress" class="form-label">Address</label>
<input type="text" class="form-control" id="validationAddress" value="XYZ - 123" required>
<div class="valid-feedback">
Correct input!
</div>
</div>
</div>
<div class="col-md-3">
<label for="validationCustom" class="form-label">Gender</label>
<select class="form-select" id="validationCustom" required>
<option selected disabled value="">Choose...</option>
<option>Male</option>
<option>Female</option>
<option>Others</option>
</select>
<div class="invalid-feedback">
Please select gender.
</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">
I have reviewed and agree to Terms of Services and Privacy Policy.
</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</button>
</div>
</form>
<script>
(() => {
'use strict'
// Fetch all the forms we want to apply custom Bootstrap validation styles to
// 获取所有我们想要应用自定义 Bootstrap 验证样式的表单
const forms = document.querySelectorAll('.needs-validation')
// Loop over them and prevent submission
// 遍历它们并阻止提交
Array.from(forms).forEach(form => {
form.addEventListener('submit', event => {
if (!form.checkValidity()) {
event.preventDefault()
event.stopPropagation()
}
form.classList.add('was-validated')
}, false)
})
})()
</script>
</body>
</html>
以下 JavaScript 代码片段会在存在无效字段时禁用表单提交。它通过为表单添加事件监听器,并在表单无效时阻止默认表单提交行为来实现这一点。
// Example JavaScript starter for disabling form submissions if there are invalid fields
// 示例 JavaScript 代码,用于在存在无效字段时禁用表单提交
(() => {
'use strict'
// Fetch all the forms we want to apply custom Bootstrap validation styles to
// 获取所有我们想要应用自定义 Bootstrap 验证样式的表单
const forms = document.querySelectorAll('.needs-validation')
// Loop over them and prevent submission
// 遍历它们并阻止提交
Array.from(forms).forEach(form => {
form.addEventListener('submit', event => {
if (!form.checkValidity()) {
event.preventDefault()
event.stopPropagation()
}
form.classList.add('was-validated')
}, false)
})
})()
浏览器默认样式
我们也可以使用浏览器默认消息而不是自定义验证消息。根据你的浏览器和操作系统,反馈样式会有所不同。
虽然 CSS 无法用来样式化这些反馈样式,但 JavaScript 仍然可以用来更改反馈文本。
尝试提交以下示例中的表单,查看浏览器默认验证消息是如何显示的。
示例
你可以使用 Edit & Run 选项来编辑并运行这段代码。
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap Form - Validation</title>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha3/dist/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha3/dist/js/bootstrap.bundle.min.js"></script>
</head>
<body>
<form class="row g-3">
<div class="col-md-4">
<label for="validationDefaultName" class="form-label">Full Name</label>
<input type="text" class="form-control" id="validationDefaultName" value="name" required>
</div>
<div class="col-md-4">
<label for="validationDefaultEmail" class="form-label">Email Id</label>
<div class="input-group">
<input type="text" class="form-control" id="validationDefaultEmail" aria-describedby="inputGroupPrepend" required>
<span class="input-group-text" id="inputGroupPrepend">@example.com</span>
</div>
</div>
<div class="col-md-4">
<label for="validationDefaultMob" class="form-label">Mobile No</label>
<input type="text" class="form-control" id="validationDefaultMob" value="" required>
</div>
<div class="col-md-6">
<label for="validationDefaultAddress" class="form-label">Address</label>
<input type="text" class="form-control" id="validationDefaultAddress" required>
</div>
<div class="col-md-3">
<label for="validationDefaultGender" class="form-label">Gender</label>
<select class="form-select" id="validationDefaultGender" required>
<option selected disabled value="">Choose...</option>
<option>Male</option>
<option>Female</option>
<option>Others</option>
</select>
</div>
<div class="form-check">
<input class="form-check-input" type="checkbox" value="" id="invalidCheck2" required>
<label class="form-check-label" for="invalidCheck2">
I have reviewed and agree to Terms of Services and Privacy Policy.
</label>
</div>
</div>
<div class="col-12">
<button class="btn btn-primary" type="submit">Submit</button>
</div>
</form>
</body>
</html>
服务端
推荐使用客户端验证,但在服务端验证的情况下,使用 .is-invalid 和 .is-valid 类来指示表单字段状态。同时考虑与这些类一起使用 .invalid-feedback。
对于无效字段,使用 aria-describedby 属性将无效反馈/错误消息链接到表单字段。(如果字段连接到其他表单文本,可以引用多个 id。)
输入组需要额外的 .has-validation 类来处理边框半径问题。
示例
您可以使用 Edit & Run 选项编辑并尝试运行此代码。
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap - Validation</title>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha3/dist/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha3/dist/js/bootstrap.bundle.min.js"></script>
</head>
<body>
<form class="row g-3">
<div class="col-md-4">
<label for="validationServerName" class="form-label">Full name</label>
<input type="text" class="form-control is-valid" id="validationServerName" value="Mark" required>
<div class="valid-feedback">
enter your name
</div>
</div>
<div class="col-md-4">
<label for="validationServerEmail" class="form-label">Email Id</label>
<div class="input-group has-validation">
<input type="text" class="form-control is-invalid" id="validationServerEmail"
aria-describedby="inputGroupPrepend3 validationServerEmailFeedback" required>
<span class="input-group-text" id="inputGroupPrepend3">@example.com</span>
<div id="validationServerEmailFeedback" class="invalid-feedback">
Please enter mail id.
</div>
</div>
</div>
<div class="col-md-4">
<label for="validationServerMob" class="form-label">Mobile no</label>
<input type="text" class="form-control is-valid" id="validationServerMob" value="" required>
<div class="valid-feedback">
Please enter mobile no
</div>
</div>
<div class="col-md-6">
<label for="validationServerAddress" class="form-label">Address</label>
<input type="text" class="form-control is-invalid" id="validationServerAddress"
aria-describedby="validationServerAddressFeedback" required>
<div id="validationServerAddressFeedback" class="invalid-feedback">
Please enter a valid Address.
</div>
</div>
<div class="col-md-3">
<label for="validationServer04" class="form-label">Gender</label>
<select class="form-select is-invalid" id="validationServer04" aria-describedby="validationServer04Feedback"
required>
<option selected disabled value="">Choose...</option>
<option>Male</option>
<option>Female</option>
<option>Others</option>
</select>
<div id="validationServer04Feedback" class="invalid-feedback">
Please select a valid gender.
</div>
</div>
<div class="col-12">
<div class="form-check">
<input class="form-check-input is-invalid" type="checkbox" value="" id="invalidCheckPolicy"
aria-describedby="invalidCheckFeedback" required>
<label class="form-check-label" for="invalidCheckPolicy">
I have reviewed and agree to Terms of Services and Privacy Policy.
</label>
<div id="invalidCheckFeedback" class="invalid-feedback">
You must agree before submitting.
</div>
</div>
</div>
<div class="col-12">
<button class="btn btn-primary" type="submit">Submit</button>
</div>
</form>
</body>
</html>;
支持的元素
以下表单控件和组件支持验证样式:
<textarea> 和 <input> 使用 .form-control(允许 input group 包含最多一个 .form-control)。
<select> 使用 .form-select
.form-check
示例
您可以使用 Edit & Run 选项编辑并尝试运行此代码。
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap Form - Validation</title>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha3/dist/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha3/dist/js/bootstrap.bundle.min.js"></script>
</head>
<body>
<form class="was-validated">
<div class="mb-3">
<label for="validationTextarea" class="form-label">添加评论</label>
<textarea class="form-control" id="validationTextarea" placeholder="在此输入评论" required></textarea>
<div class="invalid-feedback">
添加评论
</div>
</div>
<div class="form-check mb-3">
<input type="checkbox" class="form-check-input" id="validationFormCheck" required>
<label class="form-check-label" for="validationFormCheck">项目一</label>
<div class="invalid-feedback">无效答案</div>
</div>
<div class="form-check">
<input type="radio" class="form-check-input" id="validationFormRadio1" name="radio-stacked" required>
<label class="form-check-label" for="validationFormRadio1">项目二</label>
</div>
<div class="form-check mb-3">
<input type="radio" class="form-check-input" id="validationFormRadio2" name="radio-stacked" required>
<label class="form-check-label" for="validationFormRadio2">项目三</label>
<div class="invalid-feedback">无效答案</div>
</div>
<div class="mb-3">
<select class="form-select" required aria-label="select example">
<option value="">性别</option>
<option value="1">男</option>
<option value="2">女</option>
<option value="3">其他</option>
</select>
<div class="invalid-feedback">无效选择</div>
</div>
<div class="mb-3">
<input type="file" class="form-control" aria-label="file example" required>
<div class="invalid-feedback">文件大小超过 256kb</div>
</div>
<div class="mb-3">
<button class="btn btn-primary" type="submit" disabled>提交</button>
</div>
</form>
</body>
</html>
工具提示
要在样式化的工具提示中显示验证反馈,如果布局允许,可以将类 .{valid|invalid}-feedback 替换为 .{valid|invalid}-tooltip。
要定位工具提示,请确保父元素具有 position: relative 属性。
示例
您可以使用 Edit & Run 选项来编辑并尝试运行此代码。
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap - Validation</title>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha3/dist/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha3/dist/js/bootstrap.bundle.min.js"></script>
</head>
<body>
<form class="row g-3 needs-validation" novalidate>
<div class="col-md-4 position-relative">
<label for="validationTooltipName" class="form-label">Full Name</label>
<input type="text" class="form-control" id="validationTooltipName" value="Jhon Miller" required>
<div class="valid-tooltip">
Correct Input!
</div>
</div>
<div class="col-md-4 position-relative">
<label for="validationTooltipEmail" class="form-label">Email Id</label>
<div class="input-group has-validation">
<input type="text" class="form-control" id="validationTooltipEmail" aria-describedby="validationTooltipEmailPrepend" required>
<span class="input-group-text" id="validationTooltipEmailPrepend">@example.com</span>
<div class="invalid-tooltip">
Please enter mail id.
</div>
</div>
</div>
<div class="col-md-4 position-relative">
<label for="validationTooltipMob" class="form-label">Mobile no</label>
<input type="text" class="form-control" id="validationTooltipMob" required>
<div class="invalid-tooltip">
Please enter mobile no.
</div>
</div>
<div class="col-md-6 position-relative">
<label for="validationTooltipAddress" class="form-label">Address</label>
<input type="text" class="form-control" id="validationTooltipAddress" value="XYZ - 123" required>
<div class="valid-tooltip">
Correct Input!
</div>
</div>
<div class="col-md-3 position-relative">
<label for="validationTooltip04" class="form-label">Gender</label>
<select class="form-select" id="validationTooltip04" required>
<option selected disabled value="">Choose...</option>
<option>Male</option>
<option>Female</option>
<option>Others</option>
</select>
<div class="invalid-tooltip">
Please select a valid gender.
</div>
</div>
</div>
<div class="col-12">
<button class="btn btn-primary" type="submit">Submit</button>
</div>
</form>
<script>
(() => {
'use strict'
// 获取所有需要应用自定义 Bootstrap 验证样式的表单
const forms = document.querySelectorAll('.needs-validation')
// 遍历它们并阻止提交
Array.from(forms).forEach(form => {
form.addEventListener('submit', event => {
if (!form.checkValidity()) {
event.preventDefault()
event.stopPropagation()
}
form.classList.add('was-validated')
}, false)
})
})()
</script>
</body>
</html>