function createXHR()
{
    var request = false;
        try {
            request = new ActiveXObject('Msxml2.XMLHTTP');
        }
        catch (err2) {
            try {
                request = new ActiveXObject('Microsoft.XMLHTTP');
            }
            catch (err3) {
		try {
			request = new XMLHttpRequest();
		}
		catch (err1)
		{
			request = false;
		}
            }
        }
    return request;
}

function getPage(url, tgElement) {
	var xhr = createXHR();
	xhr.onreadystatechange=function()
	{
		if(xhr.readyState == 4 || xhr.readyState=="complete")
		{
			if(xhr.status == 200) {
				document.getElementById(tgElement).innerHTML = xhr.responseText;
			}
			else if(xhr.status == 403) {
				window.location = '.';
			}
			else {
				document.getElementById(tgElement).innerHTML = "Chyba: " + xhr.status + " " + xhr.statusText;
			}
		}
	};
	document.getElementById(tgElement).innerHTML = '<div class="ajaxStatusBar">Loading...</div>' + document.getElementById(tgElement).innerHTML;
	xhr.open("GET", url, true);
	xhr.send(null);
}

window.setInterval("getPage('/session_holder.php','xhrss')",120000);