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