パスワードの表示/非表示を切り替えるアイコンボタンを実装する

以下のようにHTMLとJavaScriptを組み合わせて実装します。以下は、ログイン画面でパスワードの表示/非表示を切り替える方法を示す例です。

login.html

<!DOCTYPE html>
<html lang="jp">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Login Page</title>
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css">
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap-icons@1.10.5/font/bootstrap-icons.css">
    <script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script>
</head>
<body>
    <div class="container mt-5">
        <div class="row justify-content-center">
            <div class="col-md-4">
                <h2>Login</h2>
                <form id="login-form">
                    <div class="mb-3">
                        <label for="username" class="form-label">Username</label>
                        <input type="text" class="form-control" id="username" required>
                    </div>
                    <div class="mb-3">
                        <label for="password" class="form-label">Password</label>
                        <div class="input-group">
                            <input type="password" class="form-control" id="password" required>
                            <button class="btn btn-outline-secondary" type="button" id="toggle-password">
                                <i class="bi bi-eye-slash" id="toggle-password-icon"></i>
                            </button>
                        </div>
                    </div>
                    <button type="submit" class="btn btn-primary">Login</button>
                </form>
            </div>
        </div>
    </div>
</body>
</html>
<script>
$(document).ready(function () {
    $('#toggle-password').click(function () {
        const passwordInput = $('#password');
        const passwordIcon = $('#toggle-password-icon');
        const type = passwordInput.attr('type') === 'password' ? 'text' : 'password';
        passwordInput.attr('type', type);

        // Toggle the icon class
        if (type === 'text') {
            passwordIcon.removeClass('bi-eye-slash').addClass('bi-eye');
        } else {
            passwordIcon.removeClass('bi-eye').addClass('bi-eye-slash');
        }
    });
 });
</script>

実施例