PHP list file and folder

function listFolderFiles($dir){
    $ffs = scandir($dir);
    echo '<ol>';
    foreach($ffs as $ff){
        if($ff != '.' && $ff != '..'){
            echo '<li>'.$ff;
            if(is_dir($dir.'/'.$ff)) listFolderFiles($dir.'/'.$ff);
            echo '</li>';
        }
    }
    echo '</ol>';
}

listFolderFiles('Main Dir');

source http://stackoverflow.com/questions/7121479/listing-all-the-folders-subfolders-and-files-in-a-directory-using-php