format-date issue in web form

Question

Hi All

I have created a form in survey123 connect and as part of that I create a unique ID which is a concat of the user ID and the current date and time:

concat(${observername},"_",format-date(once(now()), '%y%m%d%H%M%S'))

This works fine in the Survey123 app eg 9359_220427140725

However if I use the webform (desktop browser) I get this result: 9359_Invalid Date

Does anyone have any suggestions?

Cheers, Chris

IsmaelChivite · Accepted Answer

once would generally be used like this:

once(concat(${observername},"_",format-date(now(), '%y%m%d%H%M%S')))

However, it is not guaranteed that ${observername} has a value when the form is loaded. You may want to consider using

concat(${observername},"_",format-date(now(), '%y%m%d%H%M%S')