/* Подгрузка выпад. списков */
function ajax(data_var, lvl_1, lvl_2) {
    var xml_http = null;
    if (window.XMLHttpRequest){
        xml_http = new XMLHttpRequest();
    }
    else if (window.ActiveXObject){
        try{
            xml_http = new ActiveXObject("Msxml2.XMLHTTP");
            }
        catch(e){
            try{
                xml_http = new ActiveXObject("Microsoft.XMLHTTP");
            }
        catch(e){}
        }
    }
    var params = lvl_1 + '=' + encodeURIComponent(data_var)
    xml_http.open('POST', 'list_' + lvl_2 + '.php?' + params, true)
    xml_http.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded')
    xml_http.onreadystatechange = function() {
        if (xml_http.readyState == 4) {
            document.getElementById('load_' + lvl_2).innerHTML = xml_http.responseText
        }
    }
    xml_http.send(params)
}