Loop through post array checking that the method is post, using key and values.

loop_through_post.php

<?php
if($_SERVER['REQUEST_METHOD']=="POST") {
  $message = "";
  foreach( $_POST as $stuff => $stuff_val ) {
      if( is_array( $stuff ) ) {
          foreach( $stuff as $thing => $thing_val) {
              $message .= "$thing : $thing_val <br>";
          }
      } else {
            $message .= "$stuff : $stuff_val <br>";
      }
  }
  echo $message;
}
?>