open window & close prior window

[Guest]

I have a server side button which I added an OnClick event to using
myButton.Attributes.Add("OnClick","myJavascriptFunction()")
Well, I want myJavascriptFunction to open a new window. But, I want it to
close the previuos "same" window if it was open and then open the window
again (so the .net code can get executed). The problem is that the page that
myButton sits on is refreshing, causing my javascript code to not remember
the window it had already opened.

I read something about a hidden frame for pulling this off but haven't
totally understood how to do this? Any ideas?