check proxy

function check_proxy($proxy){
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_PROXY, $proxy);
  curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  curl_setopt($ch, CURLOPT_HEADER, 1);
  $curl_scraped_page = curl_exec($ch);
  curl_close($ch);
  return $curl_scraped_page;
}