// Fetch all the forms we want to apply custom Bootstrap validation styles to
let 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
  );
});