var xhr;
var idVysledku;

function vytvorXHR()  {   
  var xhr;
  try {   
    xhr = new XMLHttpRequest();   
  } catch(e) {
    var MSXmlVerze = new Array('MSXML2.XMLHttp.6.0','MSXML2.XMLHttp.5.0','MSXML2.XMLHttp.4.0','MSXML2.XMLHttp.3.0','MSXML2.XMLHttp.2.0','Microsoft.XMLHttp');   
    for (var i = 0; i <= MSXmlVerze.length; i ++) {   
      try {   
        xhr = new ActiveXObject(MSXmlVerze[i]);     
        break;   
      } catch(e) {}   
    }   
  }   
  if  (!xhr)   
    alert("Došlo k chybě při vytváření objektu XMLHttpRequest!");   
  else
     return xhr;
}

function kontrola(co, id) {
  xhr=vytvorXHR();
  var hodnota = document.getElementById(id).value;
  var heslo1 = document.getElementById("heslo1").value;
  idVysledku = id + "1";
  document.getElementById(idVysledku).innerHTML = "<img src='style/images/loading.gif' alt='loading' />";
  if (xhr.readyState == 4 || xhr.readyState == 0) {
    xhr.onreadystatechange = zmenaHlaseni;
    xhr.open("GET", "kontrola.php?co=" + co + "&hodnota=" + hodnota + "&hodnota2=" + heslo1, true);
    xhr.send(null);
  }  
}
function zmenaHlaseni() {   
  if (xhr.readyState == 4) {    
    var vysledek = document.getElementById(idVysledku);
    vysledek.innerHTML = xhr.responseText;
    over();
    vysledek.style.visibility = "visible";
  }   
}
function over() {
  var i=1;
  while (i<7) {
    var zkouska = document.getElementById("test"+(i++)).value;
    if (zkouska=="ko") {var ko=1; break;}
  }
  if (ko==1)  {
    document.getElementById("registrovat").disabled="disabled";
    document.getElementById("overeni").src="disconnect.png";
  } else {
    document.getElementById("registrovat").disabled="";
    document.getElementById("overeni").src="connect.png";
  }
}

function random_user()  {
  xhr=vytvorXHR();
  var id = document.getElementById("id_uzivatele").value;
  idVysledku = "random_user";
  document.getElementById(idVysledku).innerHTML = "<img src='style/images/loading.gif' alt='' style='margin-top: 90px;' /><input type='hidden' name='id_uzivatele' id='id_uzivatele' value='0' />";
  if (xhr.readyState == 4 || xhr.readyState == 0) {
    xhr.onreadystatechange = zmenaHlaseni;
    xhr.open("GET", "random.php?id="+id, true);
    xhr.send(null);
  }
}