It can make work using jQuery with the help of event handler

Handle click event of modal dialog, pass data by selecting #Id into modal and show it

Something like.,

$(document).on("click", ".open-modalDialog", function () {
     var mytxtInput1Id = $(this).data('txtInput1');
     $(".modal-body #txtInput1").val( mytxtInput1Id );
     //you have call modal to open here
     $('#addModalDialog').modal('show');
});

Assuming this is bootstrap5:

It seems like you should only get the value after the modal closes... which is what the function attached to myModalEl.addEventListener does.

event.target typical returns the element that has the event listener attached to it, but like I said in the comments in the code below, if it doesn't, then there are a million and one different ways to do so.

var myModalEl = document.getElementById('myModal');
myModalEl.addEventListener('hide.bs.modal', function (event) {
  // getElementsByName returns a list of elements, so be sure to select an element to perform on
  document.getElementsByName("name_of_hidden_element")[0].value = event.target.getElementsByName("name_of_element_inside_of_modal")[0].value
  //event.target.... should work to get the element from inside the modal, but if it doesn't there are several other ways to do so.
});