Detect when browser receives file download

Question

I have a page that allows the user to download a dynamically-generated file. It takes a long time to generate, so I\'d like to show a \"waiting\" indicator. The problem is,

Answer 1

If you don't want to generate and store the file on the server, are you willing to store the status, e.g. file-in-progress, file-complete? Your "waiting" page could poll the server to know when the file generation is complete. You wouldn't know for sure that the browser started the download but you'd have some confidence.