<ul id="sddm">
<li><a href='#'><span>Posting Management</span></a></li>
<li><a href='#'><span>Institute</span></a>
<ul>
<li><a href='#'><span>Item 1</span></a></li>
<li><a href='#'><span>Item 2</span></a></li>
</ul>
</li>
</ul>
If you are using the JavaScript purely to show and hide sub menus then you can go a pure CSS route way. You can find out more by searching for Pure CSS menus. There are quite a few CSS Menu Makers
[
^] out there which you can check out also.
If you wish to go the JavaScript way, you will just need to update your code to show and hide the inner <ul>...</li>.
I hope this helps.