代码示例：（标识：bs_form_validation）
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap 实例</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/5.1.2/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/5.1.2/js/bootstrap.bundle.js"></script>
</head>
<body>
<div class="p-4">
<h3>表单验证</h3>
<p>请尝试提交表单。</p>
<form action=/index/demo/form_current.html class="was-validated">
<div class="mb-3 mt-3">
<label for="uname" class="form-label">用户名：</label>
<input type="text" class="form-control" id="uname" placeholder="请输入用户名" name="uname" required>
<div class="valid-feedback">有效的。</div>
<div class="invalid-feedback">请填写此字段。</div>
</div>
<div class="mb-3">
<label for="pwd" class="form-label">密码：</label>
<input type="password" class="form-control" id="pwd" placeholder="请输入密码" name="pswd" required>
<div class="valid-feedback">有效的。</div>
<div class="invalid-feedback">请填写此字段。</div>
</div>
<div class="form-check mb-3">
<input class="form-check-input" type="checkbox" id="myCheck" name="remember" required>
<label class="form-check-label" for="myCheck">我同意这些条款。</label>
<div class="valid-feedback">有效的。</div>
<div class="invalid-feedback">选中此复选框以继续。</div>
</div>
<button type="submit" class="btn btn-primary">提交</button>
</form>
</div>
</body>
</html>
