var DS = {
    doAjaxPost: function(url, data, callback) {
        $.ajax({
            type: "POST",
            url: url,
            data: JSON.stringify(data),
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function(msg) {
                var obj = (typeof msg.d) ? eval(msg.d) : msg.d;
                if (callback) { callback(obj); }
            }
        });
    }
};