Swapping z-index of a div with AS

Is there some actionscript in flash to be able to swap the z-index of divs?

I have a flash menu div sitting on top of a iframe div which the content gets loaded into. The problem is that in Firefox, the text can not be selected and the scroll bar doesnt work since flash sits on top of the iframe div and blocks interaction with the content.

It works in IE though.

So what im thinking is that setting some kind of command to my buttons that when they are active to swap z-index to higher level than the iframe, and swap them back when they are not in use.

Any suggestions?