无法捕获表单选择值，php

Question

在阅读了这里的许多帖子后，关于如何捕获我的html表单中的Select值，我理解了原理，但我似乎无法在下面的代码中完美地执行它。
$ selected_val未被追加。也许它是空的？我错过了什么？提前致谢。

期望的结果：
test@test.com为A-用户，

当前结果：
test@test.com是，

下面是如何我的HTML表单看起来如下：

<form method="POST" class="subscription-form form-inline id="subscribe" role="form"> 

<h4 class="subscription-success"><i class="icon_check"></i> Thank you for requesting... </h4> 
<h4 class="subscription-error">Something Wrong!</h4> 

<select name="usertype" class="form-control input-box"> 
    <option selected value="A-user">I'm an A user</option> 
    <option value="B-user">I'm an B user</option> 
    <option value="C-user">I'm an C user</option> 
</select> 
<input type="email" name="email" id="subscriber-email" placeholder="Your Email" class="form-control input-box"> 

<button type="submit" name="submit" id="subscribe-button" class="btn btn-default standard-button">Submit</button> 

</form> 

这里是我的PHP：

<?php 
    if (isset($_POST['email']) && filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)) { 

    $selected_val = $_POST['usertype']; // Storing Selected Value In Variable 

    $e_mail = $_POST['email'] . " is a " . $selected_val . " ," . "\n"; 
file_put_contents('email-list.txt', $e_mail, FILE_APPEND | LOCK_EX); 
} 
?> 

Answer 1

您的形式缺少方法属性

Post方法应该是有

<form action="your.php" method="post"> 

Answer 2

<form>元素应该有method属性像

<form method="POST" class="subscription-form form-inline wow fadeInRight animated" data-wow-offset="10" data-wow-duration="1.5s" id="subscribe" role="form"> 

而且注意y中的我们的PHP代码，用户将点击提交按钮，查看

if (isset($_POST['submit'])) { 
    selected_val = $_POST['usertype']; // Storing Selected Value In Variable 
    $e_mail = filter_var($_POST['email'], FILTER_VALIDATE_EMAIL); 
    $e_mail = $e_mail . " - is a - " .$selected_val . " ," . "\n"; 
    file_put_contents('email-list.txt', $e_mail, FILE_APPEND | LOCK_EX); 
    }