Can i set Calendar Date in repeater hidden field

Hello,
I wanted to ask if it is possible that I can automatically load the date entered into a calendar field (field_calendar3, Data25 [datum], ID: datum) into a hidden field in a repeater at the same time? And how are you?

Hidden field (field_hidden32)
Name: group [{var: area_repeater2.key}] [datum]
ID: date_ {var: area_repeater2.key}
value: {data: field_calendar3.datum}
​
F.

Sure don't see why not. Is it not working for you?

The way the settings are now is not. Do I have to set up an event in the Calendar field and trigger a javascript function ...

The "{data:field_calendar3.datum}" value would have to be available at the time the form loads so if that's not the case then yes you'd need a js function.

<script>
$("#datum").on("change", function(){
 $("#datum_1").val(parseInt($("#datum").val()));
});
</script>
in load under Actions?

Replace $ with jQuery
​
Put it in a Custom Javascript under Views
​
Also....... It appears to only change the value of the #datum_1 field, which won't be much use? You probably want to have a 'starts with' or 'ends with' identifier and target the name of the repeater field.
​
Also also you can just add a function name as a field event for on change in the field settings. The name of the function goes in the right hand input not the left.

The problem is actually:
​
The user first enters the date and other data into a table1 in the form.
The date is also "still" stored in Table1.
The date data is stored in the table 2 via repeater area.
For later processing, it is better if the date is also stored in Table2.
But I do not want the user in the Repeater area constantly has to enter the same date.
Therefore I thought that it is easy to copy the date into a hidden field in the repeater via an event action in the calender field.
​
No idea if that's the way to go.

Why not use the date value as the "value" of the date field then?

calendar: field_calendar3 (black lable)
name: Fund[datum]
ID: datum
​
in the hidden field in repeater area:
name: group[{var:area_repeater2.key}][datum]
ID: datum_{var:area_repeater2.key}
Value: {var:field_calendar3.Fund.datum}
not working...

Well if you put {var:field_calendar3.Fund.datum} in a custom HTML block, does anything show? I bet you it doesn't. Have a look at your debug to see what data you've made available

Array
(
    [chronoform] => beobachtungen
    [event] => submit
    [Data25] => Array
        (
            [datum] => 2019-06-20
            [fundort] => Klosterfelde am Waldrand, BAR
        )

    [Data26] => Array
        (
            [beobachter] => Fred Ockruck
        )

    [Fund] => Array
        (
            [teilnehmer] => 
            [datenweitergabe] => 1
        )

    [group] => Array
        (
            [1] => Array
                (
                    [species] => lathonia, Issoria, (Linnaeus, 1758)
                    [anzahl] => 1
                    [stadium] => Imago
                    [geschlecht] => männl
                    [beobachtung] => Am Licht
                    [bestimmung] => Augenschein
                    [mapid_v] => 3
                    [datum] => 
                    [bemerkung] => 
                    [photo] => 
                )

        )