function ajax(stranka, kam){
  var httpRequest;
  if(typeof window.ActiveXObject != 'undefined'){
    httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
  } else {
    httpRequest = new XMLHttpRequest();
  }
  httpRequest.open("GET", stranka, true);
  httpRequest.onreadystatechange= function (){
    processRequest(httpRequest, kam)
  };
  httpRequest.send(null);
}
function processRequest(httpRequest, kam){
  if (httpRequest.readyState == 4){
    if (( httpRequest.status >= 200 && httpRequest.status < 300 ) || httpRequest.status == 304){
      if (typeof kam == 'string'){
        document.getElementById(kam).innerHTML = httpRequest.responseText;
      }
      if (typeof kam == 'function'){
        kam(httpRequest.responseText);
      }
    }
    else {
      alert("Chyba pri nacitani stanky " + httpRequest.status +" : "+ httpRequest.statusText);
    }
  }
  else {
    if (typeof kam == 'string' && kam != ''){
      document.getElementById(kam).innerHTML = 'Nacitam...';
    }
  }
}