function getCities() {
    var url = "index.php";
    var par1 = 2;
    var par2 = document.getElementById('folder').value;
    var pars = "eID=myext&par1="+par1+"&par2="+par2;
    var myAjax = new Ajax.Request(url, {method: 'get', parameters: pars, onComplete: updateCities});
}
function updateCities(orgRequest) {
    var xmldoc = orgRequest.responseXML;
    var result = xmldoc.getElementsByTagName("data")[0].firstChild.data;
    document.getElementById('citydiv').innerHTML = result;
}