function get_xml_file (url) {
   var httpreq = getHTTPObject();

   // Warunek wstpny: adres URL jest niezbdny.
   if (url == "") return;

   httpreq.open("GET", url, true);

   httpreq.onreadystatechange = function () {
      if (httpreq.readyState == 4) {
         var content = document.getElementById("content");
         content.innerHTML = "Analiza dokumentu XML...<br>";

         last_xml_response = httpreq.responseXML;
         format_rss_data ("content", last_xml_response);
      }
   }

   var content = document.getElementById("content");
   content.innerHTML = "Pobieranie dokumentu XML...<br>";
   httpreq.send (null);
}

function get_rss_feed () {

   // Pobranie wybranych kanaw RSS.
   var lbFeeds = document.getElementById("lbFeeds");
   if (lbFeeds.value != "") {
      get_xml_file (lbFeeds.value);
   }

}
