I have a script that reloads the page to get a PDF generated by PHP. I could have PHP send the file with a content disposition of 'attachment' and the browser will catch the file, open the save dialog, and general happiness follows.

My boss wants the user to be unable to do anything while this is going on. Tired of arguing the point about the benefit of handling transactions asynchronously, is there a way for me to detect in the origin page when this attachment has arrived so that I can shut of any loading indicator I have running?

Any window events fired by this? I mean, when the browser gets the response and sees it is an attachment and not a page does an event get raised in the calling page?