function post_feedback(url)
{
    var sid = document.getElementById("feedback-session");
    var email = document.getElementById("feedback-email");
    var title = document.getElementById("feedback-title");
    var msg = document.getElementById("feedback-message");
    
    var request = newRequest();
    if (request == null) return;
    request.onreadystatechange = function()
    {
	    if (request.readyState == 4) 
	    {
		    if (request.status == 200) 
		    {
		        var err = request.responseXML.getElementsByTagName("error");
		        if (err.length > 0)
		        {
		            alert(err[0].childNodes[0].nodeValue);
		        }
		        else
		        {
		            var arr = request.responseXML.getElementsByTagName("response");
		            alert(arr[0].childNodes[0].nodeValue);
		            email.value = title.value = msg.value = msg.innerText = "";
		        }  		        
		    } 
		    else alert("Ошибка запроса (Статус - " + request.status + ")");
	    }    
    }
    request.open("POST", url+"?mode=feedback", true);
    
    var params = "sid=" + sid.value;
    params += "&email=" + email.value;
    params += "&title=" + title.value;
    params += "&msg=" + (msg.value == null || msg.value == "" ? msg.innerText : msg.value);
    request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    //request.setRequestHeader("Content-length", params.length);
    //request.setRequestHeader("Connection", "close");
    request.send(params);
}