I didn't know this before now, but apparently you can attach an onload (javascript) handler, and then populate the blank page from that.

(Example: http://stackoverflow.com/questions/205087/jquery-ready-in-a-...)

I believe the question here is whether this event handler runs synchronously with the new window or iframe opening (causing the opener page rendering to hang); or fires off a bit later (asynchronously); or apparently in some browsers whether the event happens at all.

I'm sure someone who knows what they're talking about will correct me where I'm wrong ...