Is there anyway to use Javascript or possibly AJAX to cascade a Div?

Currently I have 4 divs, one for the upper left navigation, centered top navigation, upper right navigation and another div that seperates the page in half, leaving the bottom div.

I'm trying to see if I can create a collapse button for the bottom div, this will basically close that portion of the Div... the user then can click the restore button on the bottom to bring it back half way.

Any ideas, I'm not to good with Javascript, but I'm learning as I go for a project and this seems a little more advanced.

Thanks!