How much data? if your button had a client-side click handler you could open up the popup page with the data needing to be saved in the querystring. The popup page can do the save, show the saved data, and offer a close button. Does that get it? ...the parent page is completely still. The problem is the querystring severely limits the length of data you can send that way. If you allow the button on the parent page to postback that first time then you can save alot more data. hth