Validation 2.js

(()=>{
        const filterForm = document.querySelector('#filterForm');
        function submitFunc(e) {

            const field = [
                'region', 'towns', 'areas'
            ];

            let select = filterForm.querySelectorAll('select');
            let i = 0;
            let result = select.length;

            field.forEach(function(item, i, field) {

                    if(select[i].classList.contains('visible')){
                        if (select[i].value === "false") {
                            select[i].classList.add('uk-form-danger');
                        } else {
                            select[i].classList.remove('uk-form-danger');
                        }
                    }

            });

            for ( ; i < result; i++ ) {
                if(select[i].classList.contains('uk-form-danger')){
                    e.preventDefault();
                }
            }

        }
        filterForm.addEventListener('submit', submitFunc)
    })();