Bootstrap表单$ _POST为空

我正在尝试使用php和bootstrap提交电子邮件订阅时事通讯.var_dump($ _ POST)输出:array(1){'subscribe_submit'=> string(0)""}

这是我的HTML:

  

    Email:
    
    
    Submit

subscribe.php

query($sql);
$row=$result->fetch_assoc();

if($result->num_rows == 1)
{
echo "You are already subscribed to our minutes.";
}else
{
$sql = "INSERT INTO minutes (email)
VALUES ($email)";

if ($db->query($sql)) {
    echo "New record created successfully";
} else {
    echo "Error: " . $sql . "
" . mysqli_error($db);
}

$db->close();  
}
}
?>

我一整天都在绞尽脑汁想弄清楚它为什么不起作用.提前致谢.

你忘记了最重要的属性 name="email"