Congratulations! Not a minor achievement, I know.
Here's what I do, immediately after running the HTML prompt:
I think the check for "is empty" is probably to check to see if the "Escape" key as used to exit the prompt - I'm not positive.
If you learned anything interesting, please post about it. As you probably know, this is an under-documented feature, mostly because it's HTML which means it can get pretty complex (at least for me).
If you haven't already done so, you might also want to look at this: