blank page can some one check my code

<?php 
/*error_reporting(E_ALL);
ini_set('display_errors', 1);
ini_set('html_errors', 1);*/

include("include/data.php");
include("include/function.php");


if (isset($_GET["id"])) {
  $id = $_GET["id"];
  if(isset($catalog[$id])){
    $item = $catalog[$id];
  }
}

if(!isset($item)){  
  header("location:catalog.php");
  exit;
}


$pageTitle = $item["title"];
$section = null;

include("include/header.php"); ?>

<div class ="section page">
  <div class ="wrapper">
    <div class = "media-picture">
    <span>
        <img src="<?php echo $item["img"]; ?>" alt="<?php echo $item["title"]; ?>" />

     </span>
      </div>
    <div class ="media-details">
        <h1><?php echo $item["title"];?></h1>
        <table>
          <tr>
            <th>Category</th>
            <td><?php echo $item["category"];?></td>
          </tr>
          <tr>
            <th>Genre</th>
            <td><?php echo $item["genre"];?></td>
          </tr>
          <tr>
            <th>Format</th>
            <td><?php echo $item["format"];?></td>
          </tr>
          <tr>
            <th>Year</th>
            <td><?php echo $item["year"];?></td>
          </tr>
          <?php if(strtolower($item["category"])=="books"){?>
          <tr>
            <th>Authors</th>
            <td><?php echo implode(", ", $item["authors"]);?></td><!--use implode method to seperate authors in commas -->
          </tr>

          <tr>
            <th>Publisher</th>
            <td><?php echo $item["publisher"];?></td>
          </tr>
          <tr>
            <th>ISBN</th>
            <td><?php echo $item["isbn"];?></td>
          </tr>


            <?php } else if(strtolower($item["category"])=="movies") { ?>
            <tr>
            <th>Director</th>
            <td><?php echo $item["director"];?></td>
          </tr>
             <?php }?>
      </table>
      </div>
  </div>
</div>