WordPress contact form 7 to show the form dropdown menus as like [closed]

— Append parent_ to all your top level options’ values like: parent_Course A, parent_Course B
— Also add extra options with the value as “endparent” something like below structure

parent_Course A:
  course 1
  course 2
  course 3
  course 4
endparent
parent_Course B:
  course 1
  course 2
  course 3
endparent

Code:

// contact us form - change out optgroup labels
$(function() {
    // search for parent_ items
    var foundin = $('option:contains("parent_")');
    $.each(foundin, function(value) {
         var updated = $(this).val().replace("parent_","");
        // find all following elements until endparent
        $(this).nextUntil('option:contains("endparent")')
        .wrapAll('<optgroup label="'+ updated +'"></optgroup');
    });
    // remove placeholder options
    $('option:contains("parent_")').remove();
    $('option:contains("endparent")').remove();
});