RegisterStartupScript and browser page refresh

[Moe Sisko]

Using ASP.NET 2.0 .

When a certain button is pressed on Page "A", I perform some server side
processing, then call Page.ClientScript.RegisterStartupScript to attach
some javascript, which causes a new browser window to open on Page "B". This
all works fine.

However, if the user then performs a refresh on the browser on Page "A",
then this causes the RegisterStartupScript to run again, causing Page "B" to
open up again. Is there any way I can prevent the browser refresh from
opening Page "B" again ?

Thanks