email_validate_modal.js

 $('#myModal').on('submit', function(e) {
        var rex = /^[\w-]+(\.[\w-]+)*@([a-z0-9-]+(\.[a-z0-9-]+)*?\.[a-z]{2,6}|(\d{1,3}\.){3}\d{1,3})(:\d{4})?$/
        var email = $('#email');
        if(!email.val()){
          $('#error-show').html("<small>* Email required</small>");
          e.preventDefault();
        }else{
          if(!rex.test(email.val())){
            $('#error-show').html("<small>* Invalid email</small>");
            e.preventDefault();
          }
       }
      });