How to get the ID by CSS class name in jquery

Hi Everyone,
                    I have more div in my page. I want to get the div id in runtime. I have two CSS class. one is expanded and another one is action. i want to get the id that I used the class name action not to get the expanded and expanded action. I used two class name in some div. but i don't want to get. Only used in action. How to do?...

Thanks In Advanced