If you want it to work like it does in the browser, then I'd suggest publishing to the web in the first place. If you are thinking of using the desktop export with remote-loaded content, then you're using the desktop export like your own mini browser, so you may as well just cut out the separate download and use an actual browser.
Otherwise you have to come up with your own auto-update scheme, such as checking a URL once a day to see if a newer version is available, and prompting the user if so.