Seems like the best option may be to add the disabled attribute to the button, as well as provide an aria-live section with a message stating that the form is i

Seems like the best option may be to add the disabled attribute to the button, as well as provide an aria-live section with a message stating that the form is in the process of submittal. Of course then you'll have to handle removing the disabled attribute, as well as providing a message either stating the submittal was successful, or that an error occurred. I get that HTML wasn't supposed to be an application platform, but it's what we've got for now, and all we can do is work with what we have and keep pushing forwards for better standards or a better application delivery method (which is tough, since deployment as HTML is just so easy as compared to updating a rich client application).