Paypal Payment Integration not returning any values - php

Question

This is my code in PHP for paypal payment integration.Payments are being done successfully. The response URL should be http://codaty.com/success.php?tx=83437E384950D&st=Completed&amt=10.00&cc=USD&cm=&item_number=1 .But I am getting the URL as http://codaty.com/success.php. I am not getting any parameters in return. Is this the right method for integration. Can I get a sample code for reference.
$paypal_url='https://www.paypal.com/cgi-bin/webscr';
$paypal_id='codaty#outlook.com';
<form action="<?php echo $paypal_url; ?>" method="post" name="frmPayPal1">
<input type="hidden" name="business" value="<?php echo $paypal_id; ?>">
<input type="hidden" name="cmd" value="_xclick">
<input type="hidden" name="item_name" value="QR Code">
<input type="hidden" name="item_number" value="1">
<input type="hidden" name="credits" value="510">
<input type="hidden" name="userid" value="<?=$session_userid?>">
<input type="hidden" name="amount" value="0.10">
<input type="hidden" name="cpp_header_image" value="http://codaty.com/images/logo.png">
<input type="hidden" name="no_shipping" value="1">
<input type="hidden" name="currency_code" value="USD">
<input type="hidden" name="handling" value="0">
<input type="hidden" name="cancel_return" value="http://codaty.com/cancel.php">
<input type="hidden" name="return" value="http://codaty.com/success.php">
<input type="image" src="images/card03.png" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!" class="img-responsive">
<img alt="" border="0" src="https://www.sandbox.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1">
</form>

Answer 1

Add addition Return method input hidden field <input type="hidden" name="rm" value="2">
1 — the buyer's browser is redirected to the return URL by using the GET method, but no payment variables are included.
2 — the buyer's browser is redirected to the return URL by using the POST method, and all payment variables are included.
And then in success.php :
echo "<pre>";
print_r($_POST);
More details : HTML Variables for PayPal Payments Standard