我的密码重置脚本一直告诉我填写所有字段

Question

当您想要重置密码以仅输入电子邮件时，我一直在尝试删除输入用户名的必要性。我无法理解这里的区别是什么因为我已经删除了html中的用户名部分，然后它告诉我必须填写所有字段，即使我不需要用户名字段，如果我添加它回来然后它应该工作，即使我的PHP代码不需要用户名。

旧的重置表格

<div aria-hidden="true" aria-labelledby="myModalLabel" role="dialog" tabindex="-1" id="myModal" class="modal fade">
    <form method="POST">
        <div class="modal-dialog">
            <div class="modal-content">
                <div class="modal-header">
                    <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
                    <h4 class="modal-title">Forgot Password ?</h4>
                </div>
                <div class="modal-body">
                    <p>Enter your user name below.</p>
                    <input type="text" id="username" name="username" placeholder="User Name" class="form-control placeholder-no-fix" autocomplete="off" required>
                </div>
                <div class="modal-body">
                    <p>Enter your e-mail address below.</p>
                    <input type="email" id="email" name="email" placeholder="Email" class="form-control placeholder-no-fix" autocomplete="off" required>
                </div>
                <div class="modal-footer">
                    <button data-dismiss="modal" class="btn btn-default" type="button">Cancel</button>
                    <button id="reset" class="btn btn-success" type="button">Reset</button>
                    <hr>
                    <div id="result"></div>
                </div>
            </div>
        </div>
    </form>
</div>

新的重置表格

<div aria-hidden="true" aria-labelledby="myModalLabel" role="dialog" tabindex="-1" id="myModal" class="modal fade">
            <form method="POST">
                <div class="modal-dialog">
                    <div class="modal-content">
                        <div class="modal-header">
                            <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
                            <h4 class="modal-title">Forgot Password ?</h4>
                        </div>
                        <div class="modal-body">
                            <p>Enter your e-mail address below.</p>
                            <input type="email" id="email" name="email" placeholder="Email" class="form-control placeholder-no-fix" autocomplete="off" required>
                        </div>
                        <div class="modal-footer">
                            <button data-dismiss="modal" class="btn btn-default" type="button">Cancel</button>
                            <button id="reset" class="btn btn-success" type="button">Reset</button>

                            <hr>
                            <div id="result"><?php print_r($_POST)?></div>
                        </div>
                    </div>
                </div>
            </form>
        </div>

PHP代码：

if(isset($_POST['action']) && $_POST['action'] == 'reset') {

        if(isset($_POST['email'])
            && is_string($_POST['email'])
            && !empty($_POST['email'])) {

            if (!filter_var($_POST['email'], FILTER_VALIDATE_EMAIL) === false) {
                $email = $_POST['email'];

                $stmt = $pdo->prepare('SELECT * FROM users WHERE UserEmail = :UserEmail');
                $stmt->execute(array(':UserEmail' => $email));

                if($stmt->rowCount() > 0) {
                    $new_password = substr(md5(rand(1,100000)), 0, 8);

                    $stmt = $pdo->prepare('UPDATE users SET UserPassword = :UserPassword WHERE UserEmail = :UserEmail');
                    $stmt->execute(array(':UserPassword' => md5($new_password), ':UserEmail' => $email));

                    $subject = 'Password recovery';
                    $txt = 'Your account password has been reset.';
                    $txt .= 'Your new account password is: '.$new_password.'';
                    $headers = "From: ".$RecoveryEmail."" . "\r\n" .
                    "CC: ".$RecoveryEmail."";

                    mail($email,$subject,$txt,$headers);
                } else {
                    echo('User with these credentials does not exist.');
                }
            } else {
                echo('The entered E-mail is invalid.');
            }
        } else {
            echo('Fill all fields correctly.');
        }
    }