var http_request = false;

    function makeRequest(object, url) {

        http_request = false;
        if (window.XMLHttpRequest) { // Mozilla, Safari,...
            http_request = new XMLHttpRequest();
            if (http_request.overrideMimeType) {
                http_request.overrideMimeType('text/xml');
                // Przeczytaj o tym wierszu poniżej
            }
        } else if (window.ActiveXObject) { // IE
            try {
                http_request = new ActiveXObject("Msxml2.XMLHTTP");
            } catch (e) {
                try {
                    http_request = new ActiveXObject("Microsoft.XMLHTTP");
                } catch (e) {}
            }
        }

        if (!http_request) {
            alert('Poddaję się :( Nie mogę stworzyć instancji obiektu XMLHTTP');
            return false;
        }
        http_request.onreadystatechange = function() { changeContents(object, http_request); };
        http_request.open('GET', url, true);
        http_request.send(null);

    }

    function alertContents(http_request) {

        if (http_request.readyState == 4) {
            if (http_request.status == 200) {
                alert(http_request.responseText);
            } else {
                alert('Wystąpił problem z zapytaniem.');
            }
        }

    }
    
    function changeContents(object, http_request) {
        if (http_request.readyState == 4) {
            if (http_request.status == 200) {
                change_html(object, http_request.responseText);
            } else {
                alert('Wystąpił problem z zapytaniem AJAX.');
            }
        }
    }
    
function change_html(object, html) {
  if (document.getElementById) {
    document.getElementById(object).innerHTML = html;
  }

  else if (document.layers && document.layers[object] != null) {
    document.layers[object].innerHTML = html;
  }
  else if (document.all) {
    document.all[object].innerHTML = html;;
  }
  return false;
}