const demoForm = document.getElementById('demoForm');// Query the submit buttonconst submitButton = demoForm.querySelector('button[type="submit"]');FormValidation.formValidation(demoForm,{fields: {...},plugins: {...},}).on('core.form.valid', function() {// Disable the submit buttonsubmitButton.setAttribute('disabled', true);// Do something else such as sending the form to back-end via Ajax request// ...});