https://cleanemail.com/user/sites/cleanemail.com/plugins/simplesearch/js/simplesearch.js

1((function(){
2    var findAncestor = function(el, selector) {
3        while ((el = el.parentElement) && !((el.matches || el.matchesSelector).call(el, selector))) {}
4        return el;
5    };
6
7    var fields = document.querySelectorAll('input[name="searchfield"][data-search-input]');
8    fields.forEach(function(field) {
9        var form = findAncestor(field, 'form[data-simplesearch-form]'),
10            min = field.getAttribute('min') || false,
11            location = field.getAttribute('data-search-input'),
12            separator = field.getAttribute('data-search-separator');
13
14        if (min) {
15            var invalid = field.getAttribute('data-search-invalid');
16            field.addEventListener('keydown', function() {
17                field.setCustomValidity(field.value.length >= min ? '' : invalid);
18            });
19        }
20
21        form.addEventListener('submit', function(event) {
22            event.preventDefault();
23
24            if (field.checkValidity()) {
25                window.location.href = location + separator + field.value;
26            }
27        });
28    });
29})());