var recno = 0;

function ukaz_recenzi(recno)
{
    if (window.ActiveXObject)
    {
        httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
    }
    else {
        httpRequest = new XMLHttpRequest();
    }

    httpRequest.open("GET", "pet_recenzi.php?recno=" + recno, true);
    httpRequest.onreadystatechange= function () {processRequest(); } ;
    httpRequest.send(null);

    return false;
}

function processRequest()
{
    if (httpRequest.readyState == 4)
    {
        if(httpRequest.status == 200)
        {
            document.getElementById('td_pet_recenzi').innerHTML = httpRequest.responseText;
        }
    }
}

function ukaz_dalsi_recenzi()
{
    recno = (++recno < 5) ? recno : 0;

    ukaz_recenzi(recno);

    setTimeout('ukaz_dalsi_recenzi()', 13000);
}

window.onload = function() {
    setTimeout('ukaz_dalsi_recenzi()', 18000);
}