While opting for any web-to-print solution, you need to discuss with your team and some of your end users and know their opinions about your decisions. In this article we list down some questions you need to ask yourself.
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions.
Consider email address RFCs:
Look at HTML5 form input element (with type=email) regex pattern: