List files of a directory

<?php
 
  echo 'Contents:<br />' . "\n";
  $d = dir ('./');
 
  while (false !== ($entry = $d->read())) {
    if (is_dir($entry)) {
 
    } else {
      $ext = strtolower(substr($entry, strrpos($entry, '.')));
      if (in_array($ext, array('.jar','.png','.gif','.jpg'))) {
        echo '<a href="' . $entry . '">' . $entry . '</a><br />' . "\n";
      }
    }
 
  }
 
?>