ext中 ajax同步的方法

SyncAjax = function(url) {

    function createXhrObject() {
        var http;
        var activeX = ["MSXML2XMLHttp.5.0", "MSXML2XMLHttp.4.0", "MSXML2.XMLHttp.3.0",
                       "MSXML2.XMLHttp", "Microsoft.XMLHttp"];

        try {
            http = new XMLHttpRequest();
        } catch (e) {
            for (var i = 0; i < activeX.length; ++i) {
                try {
                    http = new ActiveXObject(activeX[i]);
                    break;
                } catch (e) {
                    UICtrl.WriteToPhoneMessageBox('生成' + activeX[i] + '失败！');
                }
            }
        } finally {
            return http;
        }
    };

    var conn = createXhrObject();

    if (conn) {
        conn.open("POST", url, false);
        conn.send(null);

        if (conn.responseText != '') {
            return Ext.decode(conn.responseText);
        } else {
            UICtrl.WriteToPhoneMessageBox('服务器出现错误请稍后再试！');
        }
    } else {
        UICtrl.WriteToPhoneMessageBox('创建HTTP请求失败！');
    }
};