Email Address Validator is a PHP class that allows the developer to validate email addresses according to the RFC 5321 or RFC 5322 standards. It can also check to see if the domain can be resolved to MX RRs. Acceptable local-parts include dot-atom, quoted string, and obsolete. Acceptable domains include domain name, IPv4 address, IPv6 address, and IPv4-mapped IPv6 address. Folding white spaces and nested comments are also supported.