// Ajax post
function xml_httpPost(strURL, querystring, ret_func)
{
    var xmlHttpReq = false;
    var self = this;
    // Mozilla/Safari
    if (window.XMLHttpRequest) {
        self.xmlHttpReq = new XMLHttpRequest();
    }
    // IE
    else if (window.ActiveXObject) {
        self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
    } else {
        alert ("Can`t send request! Your browser don`t support XMLRequest");
        return false;
    }

    self.xmlHttpReq.open('POST', strURL, true);
    self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    self.xmlHttpReq.onreadystatechange = function() {
        if (self.xmlHttpReq.readyState == 4) {
            if (ret_func) {
                ret_func(self.xmlHttpReq.responseText, self.xmlHttpReq.responseXML);
            }
        }
    }
    self.xmlHttpReq.send( querystring );
}

function addEvent (el, evname, func)
{
    if (el.attachEvent) { // IE
        el.attachEvent("on" + evname, func);
    } else if (el.addEventListener) { // Gecko / W3C
        el.addEventListener(evname, func, true);
    } else {
        el["on" + evname] = func;
    }
}

function removeEvent (el, evname, func)
{
    if (el.detachEvent) { // IE
        el.detachEvent("on" + evname, func);
    } else if (el.removeEventListener) { // Gecko / W3C
        el.removeEventListener(evname, func, true);
    } else {
        el["on" + evname] = null;
    }
}