Layer overwriting footer

I have a javascript dropdown that shows and hides another div layer depending on the selection, however the layer it unhides seems to sit on top of the footer layer when i would rather have it push the footer down as far as needed. also IE and Mozilla seem to handle it quite differently.

The code is at http://testing.kdn.co.nz/fw/

any help would be appreciated. cheers!

Remove position:absolute; from #footer