// Example starter JavaScript for disabling form submissions if there are invalid fields $(function () { 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 ); }); });