Response.Redirect to new window from within IFrame?

[Guest]

Hi

I've got a situation where I need to direct a Response.Redirect to a new
window from within a page embedded within an IFrame.

Currently, we have a page embedded within an IFrame that presents a list of
items to the user in a drop-down list. According the the item selected, one
of two things can happen when they click on a button next to the drop-down:

a) The user is redirected to another page, which is itself displayed inside
the IFrame

or

b) The user is redirected to a new page that is not be embedded in the IFrame

The decision on which method to use is only known at runtime as the
drop-down is populated from a database table. The table has an ExternalUrl
field that denotes the redirection will be external to our site and should
not use the IFrame.

I've been hitting my head against the proverbial brick-wall trying to figure
this one out?

Any ideas? JavaScript is an option, but admittedly is not my strong-point.

Thanks

Ben