There already exists at least one popular js validation framework which removes Gmail (and others) subaddresses per default in its "normalizeEmail" method: http

There already exists at least one popular js validation framework which removes Gmail (and others) subaddresses per default in its "normalizeEmail" method: https://github.com/validatorjs/validator.js/blob/master/src/lib/normalizeEmail.js https://github.com/validatorjs/validator.js/blob/master/src/...