function ddcurl_login($url, $username, $password) {
  $ch = curl_init();

  $post_data = array(
    'username' => $username,
    'password' => $password
  );
  //$post_data = "username=$username&password=$password";

  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_FAILONERROR, 1);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookie.txt');
  curl_setopt($ch, CURLOPT_COOKIEFILE, 'cookie.txt');
  curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/4.0 (compatible; MSIE 6.0; Windows 98)');
  curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);
  $data = curl_exec ($ch);

  curl_close ($ch);
  return $data;
}