https://bier-guide.net/modules/custom/ep_blocks/js/ep_blocks.js?tltmr1

1/**
2 * @file
3 * Main js file for ep_blocks module.
4 */
5(function ($, Drupal) {
6    Drupal.behaviors.ep_blocks = {
7        attach: function(context, settings) {
8            var homeSearchForm = '#homepage-search-form ';
9            // Default, disable the search button from homepage search form.
10            $(homeSearchForm + '.homepage-search-button ').attr('disabled', 'disabled');
11
12            $(document).ajaxStart(function() {
13                $(homeSearchForm + '.homepage-search-button ').attr('disabled', 'disabled');
14            });
15            $(document).ajaxStop(function() {
16                // If ajax stop, check if user has wrote something in search input, to activate the search button.
17                if (($(homeSearchForm + 'input[name="search_input"]').val().trim()).length > 2) {
18                    $(homeSearchForm + '.homepage-search-button ').attr('disabled', false);
19                }
20            });
21
22            // When return from search, check if search input is not empty, to enable the search button.
23            if (($(homeSearchForm + 'input[name="search_input"]').val().trim()).length > 2) {
24                $(homeSearchForm + '.homepage-search-button').attr('disabled', false);
25            }
26            // Check if user write min 3 char in search input to enable the search button
27            $(homeSearchForm + 'input[name="search_input"]', context).keyup(function (e) {
28                $(homeSearchForm + '.homepage-search-button').attr('disabled', 'disabled');
29                if (($(this).val().trim()).length > 2) {
30                    $(homeSearchForm + '.homepage-search-button').attr('disabled', false);
31                }
32            });
33            // Check if user paste a text in search input to enable the search button.
34            $(homeSearchForm + 'input[name="search_input"]', context).on('paste', function () {
35                $(homeSearchForm + '.homepage-search-button').attr('disabled', 'disabled');
36                var that = this;
37                setTimeout(function() {
38                    // Gets the copied text after a specified time (100 milliseconds).
39                    if (($(that).val().trim()).length > 2) {
40                        $(homeSearchForm + '.homepage-search-button').attr('disabled', false);
41                    }
42                }, 100);
43            });
44        }
45    }
46})(jQuery, Drupal);