Data not being posted. Please review my code - php

Question

I am trying to post the values as shown in the script from an HTML form. I have confirmed that the form is successfully submitting the data. However, when I try to test the values being submitted using the isset() script, I get nothing at all. I am also posting my function to see if I am making an error there.
if(isset($_POST['submit']) && !empty($_POST['submit'])) {
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
// require_once('mystuff/functions.php');
echo $to_account = test_input($_POST['to_account']);
echo $to_email = test_input($_POST['to_email']);
echo $amount = test_input($_POST['amount']);
echo $pin = test_input($_POST['pin']);
} else {
echo "Probably the data was not submitted";
}
<div class="container">
<h2>Transfer:</h2>
<form action="transCtrl.php" method="POST">
<div class="form-group">
<label for="to_account">To Account</label>
<input type="text" class="form-control" id="to_account" name="to_account" required pattern="[A-Z0-9]{13}">
</div>
<div class="form-group">
<label for="to_email">To Email:</label>
<input type="email" class="form-control" id="to_email" name="to_email" pattern="[a-z0-9._%+-]+#[a-z0-9.-]+\.[a-z]{2,}$" required>
</div>
<div class="form-group">
<label for="amount">Amount</label>
<input type="number" class="form-control" id="amount" name="amount" required min="100">
</div>
<div class="form-group">
<label for="pin">8 Digit PIN</label>
<input type="text" class="form-control" id="pin" name="pin" pattern="[0-9]{8}" required>
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>
</div>

Answer 1

Instead this
if(isset($_POST['submit']) && !empty($_POST['submit'])) {
Use this:
if($_SERVER["REQUEST_METHOD"] == "POST") {
You don't have a $_POST['submit'] variable.