A very common need in PHP-based Web applications is to validate email addresses. An email address, at its most basic contains the @ and a dot and no spaces or special characters, so it’s pretty easy coming up with a regular expression that will fit this most simple restriction. However, if you want a full-on precise regular expression, that takes an immense amount of code (the full email validation pattern takes up almost a page of code). An alternative, then is to use the EmailAddressValidation class, created by Added Bytes and now hosted on Google Code.
After you’ve downloaded the code and put it on your server, you use it like so:
require('/path/to/EmailAddressValidator.php');
$emailValidator = new EmailAddressValidator();
if ($emailValidator->check_email_address('test@example.org')) {
// Email address is technically valid.
} else {
// Email not valid.
} 
