<?php

$host = "myHost"; //hidden
$pw = "myPW"; //hidden
$username = "myUser"; //hidden
$dbname = "myDB"; //hidden

//phpinfo();

$con = mysqli_connect($host, $username, $pw, $dbname);
//echo "<pre>";
//print_r($con);
//echo "</pre>";

function fill_brand($con)
{
  $output = '';
  $sql = "SELECT * FROM hersteller";
  $result = mysqli_query($con, $sql);

  while ($row = mysqli_fetch_array($result))
  {
    $output .= '<option value="'.$row["brand_id"].'">'.$row["brand_name"].'</option>';
  }

  return $output;
}


function fill_models($con)
{
  $output = '';
  $sql = "SELECT * FROM modelle";
  $result = mysqli_query($con, $sql);

  while ($row = mysqli_fetch_array($result))
  {
    $output .= '<div class="col-md-3">';
    $output .= '<div style="border:1px solid #ccc; padding:20px; margin-bottom:20px;">'.$row["model_name"].'';
    $output .= '</div>';
    $output .= '</div>';
  }
  return $output;

}

?>


<div class="container">
  <h3>
    <select name="brand" id="brand">
      <option value ="">Show all Products</option>
      <?php echo fill_brand($con); ?>
    </select>
    <br /><br />
    <div class="row" id="show_model">
      <?php echo fill_models($con);?>
    </div>
  </h3>
</div>