Regex validation for Email Address
I remember having read somewhere (possibly in another Code Review answer) that for an e-mail address, the simplest and most effective validation you can do is to make sure it contains an @. Making it more restrictive than that can often be a risk of invalidating some valid e-mails. You'd be surprised at some examples of valid e-mail addresses.

As an additional example, see the "almost RFC 822 compatible regex" in this answer.

Keep it simple, and don't mark some e-mail addresses that are actually valid as invalid.

email.contains("@")


If you want to be more restrictive than this, use an existing and trusted library for the validation, don't try to make another regex.

For further reading:


http://en.wikipedia.org/wiki/Email_address#Validation_and_verification
list of email addresses that can be used to test a javascript validation script on Stack Overflow
http://codefool.tumblr.com/post/15288874550/list-of-valid-and-invalid-email-addresses