forcing a scrollbar for fixed element accomodation

i am using the jquery simplemodal plugin,

now i've set it up so that it uses a dynamic height, based on the content within it.

however i've run into a bit of a snag here, it seems that if i make the browser window smaller, it does not accomodate for the height of the simplemodal element, therefore some things within the container are hidden off-sc开发者_如何学Creen.

i've tried adding:

body {
    overflow: auto;
}

and this accomplishes nothing. in fact, the body will scroll when resized based on the content of the page, not the simplemodal element height.

is there a way for me to force scrollbars if a fixed element is overflowing?

overflow: scroll

This forces scrollbars to appear, even when not needed.

overflow:scroll;
if you only want it to show for an instance(s), put that in a class you can chain to your simplemodal element.