Create DIV And Some Other DIV's Inside It Using OnClick Event

how to create a DIV dynamically. Basicly, I have two labels, and depending on which one is clicked, I want some code to appear inside an existing DIV. Obviously, I will need to do this using javascript and the onClick event. To make things even more complicated, I also want some DIV's inside of the dynamically created DIV. So, the structure would be:

-Existing DIV
--DIV created by label being clicked
---Another DIV
---Another DIV

I hope this doesn't confuse anyone. I have some code for the existing DIV.

<DIV ID="container"><DIV ID="title">Order</DIV><DIV ID="body">Login <LABEL onclick="login()">here</LABEL>. Signup <LABEL onclick="sign_now()">here</LABEL></DIV>
</DIV>