Create directory

  if (!is_dir('temp/'))
    mkdir('temp', 0755, true);

define("MY_FILE_DOWNLOADS_DIRECTORY",                      "file-download/");

  if (!is_dir($_SERVER['DOCUMENT_ROOT'] . "/" . MY_FILE_DOWNLOADS_DIRECTORY))
  {
    mkdir($_SERVER['DOCUMENT_ROOT'] . "/" . MY_FILE_DOWNLOADS_DIRECTORY, 0777, true);
  }

Delete directory and its contents

//*******************************************************
//*******************************************************
//********** DELETE DIRECTORY AND ITS CONTENTS **********
//*******************************************************
//*******************************************************
function DeleteDirectoryAndContent ($DirectoryPath)
{
  if (is_dir($DirectoryPath))
  {
    $Files = scandir($DirectoryPath);
    foreach ($Files as $File)
    {
      if ($File !== '.' && $File !== '..')
      {
        $FilePath = $DirectoryPath . '/' . $File;
        if (is_dir($FilePath))
          DeleteDirectoryAndContent($FilePath);
        else
          unlink($FilePath);
      }
    }
    rmdir($DirectoryPath);
  }
}