function listFolderFiles($dir){
$ffs = scandir($dir);
unset($ffs[array_search('.', $ffs, true)]);
unset($ffs[array_search('..', $ffs, true)]);
// prevent empty ordered elements
if (count($ffs) < 1)
return;
echo '<ol>';
foreach($ffs as $ff){
echo '<li>'.$ff;
if(is_dir($dir."https://stackoverflow.com/".$ff)) listFolderFiles($dir."https://stackoverflow.com/".$ff);
echo '</li>';
}
echo '</ol>';
}
listFolderFiles('Main Dir');