Gary Wilson
// EMAIL DOMAINS TO BLOCK var emailList = /@(mail\.ru)\s*$/ // ALERT MESSAGE TO BE SHOWN var emailAlert = 'Sorry, your email domain is not supported.' // VALIDATion $('input[type=submit]').click(function() { $("input[type=email]").each(function() { var email = $(this).val().toLowerCase(); if (emailList.test(email)) { (this).setCustomValidity(''); } else { (this).setCustomValidity(emailAlert); } }) }); // PREVENTS ALERT FROM APPEARING WITH EACH KEYPRESS $('input[type=email]').on('input', function() { (this).setCustomValidity(''); });