一个方便AJAX开发的通用类

                    element_value=e.value;
                }
                else {
                    element_value=e.value;
                }
                element_value=encodeURIComponent(element_value);
                query_string+=and+e.name+'='+element_value;
                and="&";
            }
        }
        return query_string;
    }
}