too long

Question

I'm kinda new in PHP and I've created a form that should validate data and submit an error if any field is blank or incorrect. It doesn't tho. Even if email is wrong or any field is empty and the errors are shown it still sends an email. And the headers are not showing in the message. The only case when the errors are shown and the mail isn't send is the case when all fields are empty. Here's the code:

<?php
$NameErr = $EmailErr = $SubErr = $MessErr = "";
$Name = $Email = $Subject = $Message = "";
$header = "From: " . $Email . "Name: " . $Name . "
";
$header .= "Content-Type: text/plain";
$To = "[e-mail]";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
    if (empty($_POST["Name"])) {
        $NameErr = "Name is required";
    } else {
        $Name = test_input($_POST["Name"]);
        if (!preg_match("/^[a-zA-Z ]*$/", $Name)) {
            $NameErr = "Only letters and white space allowed!";
        }
    }
    if (empty($_POST["Email"])) {
        $EmailErr = "Email is required";
    } else {
        $Email = test_input($_POST["Email"]);
        if (!filter_var($Email, FILTER_VALIDATE_EMAIL)) {
            $EmailErr = "Invalid email format";
        }
    }
    if (empty($_POST["Subject"])) {
        $SubErr = "Subject is required";
    } else {
        $Subject = test_input($_POST["Subject"]);
    }
    if (empty($_POST["Message"])) {
        $MessErr = "Message is required";
    } else {
        $Message = test_input($_POST["Message"]);
    }
}

function test_input($data) {
    $data = trim($data);
    $data = stripslashes($data);
    $data = htmlspecialchars($data);
    return $data;
}
?>

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>">
    <p><input class="w3-input w3-padding-16" type="text" placeholder="Name" name="Name"></p>
    <span class="error"> <?php echo $NameErr; ?></span>
    <p><input class="w3-input w3-padding-16" type="text" placeholder="Email" name="Email"></p>
    <span class="error"> <?php echo $EmailErr; ?></span>
    <p><input class="w3-input w3-padding-16" type="text" placeholder="Subject" name="Subject"></p>
    <span class="error"> <?php echo $SubErr; ?></span>
    <p><input class="w3-input w3-padding-16" type="text" placeholder="Message" name="Message"></p>
    <span class="error"> <?php echo $MessErr; ?></span>
    <p>
        <button class="w3-btn w3-grey w3-padding-large w3-hover-green" type="submit" value="Submit" name="pressed">
            <i class="fa fa-paper-plane"></i> SEND MESSAGE
        </button>
    </p>
</form>
<?php
if (isset($_POST["pressed"])) {
    if (empty($NameErr && $SubErr && $MessErr && $EmailErr)) {
        mail($To, $Subject, $Message, $header);
        echo "Email sent.";
    } else {
        echo "Error.";
    }
}
?> 

Can you help me? Error validating is on and it doesn't show me any errors.

Answer 1

use isset function instead of empty() to check if the field is posted or not. example:

if (!isset($_POST["Name"])) {
...

also there is no need to check the request method, $_POST will only catch post requests.