https://www.ulaval.ca/themes/ulaval_templates/assets/ulaval/js/custom-dropdown.js?tm7i7n

1(function ($, Drupal, once) {
2  Drupal.behaviors.customDropdown = {
3    attach: function (context, settings) {
4      // Forms
5      const $elements = $(
6        once(
7          "customDropdown",
8          ".bef-exposed-form:not(.recherche--equivalences) select.form-select, .custom-select",
9          context
10        )
11      );
12      $elements.each(function () {
13        var $this = $(this),
14          numberOfOptions = $(this).children("option").length,
15          selectedOption = $(this).prop("selectedIndex");
16
17        $this.addClass("select-hidden");
18        $this.wrap('<div class="select"></div>');
19        $this.after('<div class="select-styled"></div>');
20
21        var svg =
22          '<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" width="32px" height="32px" viewBox="0 0 32 32" enable-background="new 0 0 32 32" xml:space="preserve"><path d="M3.75,6.125L16,18.313L28.25,6.125L32,9.875l-16,16l-16-16L3.75,6.125z"/></svg>';
23        var $styledSelect = $this.next("div.select-styled");
24        $styledSelect
25          .text($this.children("option").eq(selectedOption).text())
26          .append(svg);
27
28        var $list = $("<ul />", {
29          class: "select-options",
30        }).insertAfter($styledSelect);
31
32        for (var i = 0; i < numberOfOptions; i++) {
33          $("<li />", {
34            text: $this.children("option").eq(i).text(),
35            rel: $this.children("option").eq(i).val(),
36          }).appendTo($list);
37        }
38
39        var $listItems = $list.children("li");
40
41        $styledSelect.on("click", function (e) {
42          e.stopPropagation();
43          $("div.select-styled.active")
44            .not(this)
45            .each(function () {
46              $(this).removeClass("active").next("ul.select-options").hide();
47            });
48          $(this).toggleClass("active").next("ul.select-options").toggle();
49        });
50
51        $listItems.on("click", function (e) {
52          e.stopPropagation();
53          $styledSelect.text($(this).text()).append(svg).removeClass("active");
54          $this.val($(this).attr("rel"));
55          if (
56            $this.closest("form").attr("data-bef-auto-submit-full-form") == ""
57          ) {
58            $this.closest("form").trigger("submit");
59          }
60          $this.trigger("change");
61          $list.hide();
62        });
63
64        $(document).on("click", function () {
65          $styledSelect.removeClass("active");
66          $list.hide();
67        });
68      });
69    },
70  };
71})(jQuery, Drupal, once);