var produkty = ["4105882","4082398","4178248","4178256"]
	  $.each(produkty, function(k,v){
		  console.log (k+v);
	  }
	  )
	  function createCORSRequest(method, url) {
  var xhr = new XMLHttpRequest();
  if ("withCredentials" in xhr) {
    // XHR for Chrome/Firefox/Opera/Safari.
    xhr.open(method, url, true);
  } else if (typeof XDomainRequest != "undefined") {
    // XDomainRequest for IE.
    xhr = new XDomainRequest();
    xhr.open(method, url);
  } else {
    // CORS not supported.
    xhr = null;
  }
  return xhr;
}

// Make the actual CORS request.
function makeCorsRequest() {
  // This is a sample server that supports CORS.
  var url = 'https://nbsklep.pl/product/get_availability.html?variant_id=4105882&city=Bia%C5%82ystok';

    var data = new FormData();
    data.append("variant_id", produkty);

  var xhr = createCORSRequest('POST', url);
  if (!xhr) {
    alert('CORS not supported');
    return;
  }

  // Response handlers.
  xhr.onload = function() {
    var text = xhr.responseText;
    var json = JSON.parse(text);
    console.log(json)
  };

  xhr.onerror = function() {
    console.log('Woops, there was an error making the request.');
  };

  xhr.send(data);
}

makeCorsRequest()