// Example starter JavaScript for disabling form submissions if there are invalid fields (function () { 'use strict' // Fetch all the forms we want to apply custom Bootstrap validation styles to var forms = document.querySelectorAll('.needs-validation') // Loop over them and prevent submission Array.prototype.slice.call(forms) .forEach(function (form) { form.addEventListener('submit', function (event) { if (!form.checkValidity()) { event.preventDefault() event.stopPropagation() } form.classList.add('was-validated') }, false) }) })()