function handleHttpResponse(ajax) {
    frm = document.forms[0];
    campo_select = frm.cidade;

    campo_select.options.length = 0;
    results = ajax.responseText.split(";");
    campo_select.options[0] = new Option("Cidade", "");

    for(i=0; i<results.length; i++) {
        campo_select.options[i+1] = new Option(results[i],results[i]);
    }
}

function getHTTPObject() {
    var req;
    try {
        if (window.XMLHttpRequest) {
            req = new XMLHttpRequest();
            if (req.readyState == null) {
                req.readyState = 1;
                req.addEventListener("load", function () {
                    req.readyState = 4;
                    if (typeof req.onReadyStateChange == "function")
                        req.onReadyStateChange();
                }, false);
            }
            return req;
        }
        if (window.ActiveXObject) {
            var prefixes = ["MSXML2", "Microsoft", "MSXML", "MSXML3"];
            for (var i = 0; i < prefixes.length; i++) {
                try {
                    req = new ActiveXObject(prefixes[i] + ".XmlHttp");
                    return req;
                } catch (ex) {}
            }
        }
    } catch (ex) {}
    alert("XmlHttp Objects not supported by client browser");
}

function ajaxCheck() {
        var ajax;

        try {
                ajax = new ActiveXObject("Microsoft.XMLHTTP");
        } catch(e) {
                try {
                        ajax = new ActiveXObject("Msxml2.XMLHTTP");
                } catch(ex) {
                        try {
                                ajax = new XMLHttpRequest();
                        } catch(exc) {
                                var msg = "Este navegador não tem recursos para uso de processamento dinâmico.";
                                msg += "\nRecomendamos o download do Mozilla Firefox como navegador.";
                                alert(msg);
                                ajax = null;
                        }
                }
        }

        return ajax;
}