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 při načítání stránky " + httpRequest.status +" : "+ httpRequest.statusText);
        }
      }
      else
      {
        if (typeof kam == 'string' && kam != '') 
        {
            document.getElementById(kam).innerHTML = '<p>Loading...</p>';
        }
      }     
    }