I start with AppGameKit and like to program a counter which counts the days to a taget date in days in a html-page.
Is it possible to write this as a normal program and then export to html 5, or is the catalog of AGK2 functions limited in html5?

This board is for posting code snippets, not requesting them.

That functionality should be supported in the translation from agk into html5. If that's all you want to do, then agk would be overkill and cause unnecessary JS overhead as this could be done natively much more easily.