create a div element with a dynamic size

Hi,
how can I add a div element that changes it's height and width according to it's content?
I can't seem to make it work, although I've set the position css attribute of the div to "relative", and the asp controls inside it to "absolute".
I am using a dynamic gridview control that changes it's content (number of rows and cols) according to a selection og a dropdownlist. The gridview expands beyond the page's boundries.
Thanks