labacode.php

<?php
\
if( isset( $_GET[ 'Submit' ] ) ) {
  // Get input
  $id = $_GET[ 'id' ];
\
  // Check database
  $getid = "SELECT first_name, last_name FROM users WHERE user_id = '$id';";
  $result = mysqli_query($GLOBALS["___mysqli_ston"], $getid ); // Removed 'or die'
\
  // Get results
  $num = @mysqli_num_rows( $result ); // The '@' character suppresses errors
  if( $num > 0 ) {
    // Feedback for end user
    $html .= '<pre>User ID exists in the database.</pre>';
  }
  else {
    // User wasn't found, so the page wasn't!
    header( $_SERVER[ 'SERVER_PROTOCOL' ] . ' 404 Not Found' );
\
    // Feedback for end user
    $html .= '<pre>User ID is MISSING from the database.</pre>';
  }
\
  ((is_null($___mysqli_res = mysqli_close($GLOBALS["___mysqli_ston"]))) ? false : $_
}
\
?>