How to get width of DIV if display:none?

How to get width of DIV if display:none?

Hi all.
A few times I have had the need to get the width, height, or position of a DIV before using an effect (slideUP, show, etc). I found that in order for the effect to work I was required to use display:none which works great for the effect but I can no longer get the DIV's properties until it is displayed.

So in this question I am asking if it is possible to get the properties of a DIV when display is set to none.

(in another question I will ask about the requiring of display:none for using revealing effects)

Thanks
RW