sim.plified.com

For web developers, validating email addresses is just part of what it means to accept user input.  One of the challenges I find is that email validation does not often stay up to date with the changes in email.  For instance, Gmail allows for cool features like adding a +anything to the end of your email address.  Many regex email validation strings do not allow for this useful function.  Well, in designing the signup for patterntap.com I ran into this, when of course initially my regex did not allow for the gmail + or even a four letter domain name (e.g. .info)  So.. here is my updated regex for PHP.  Hope you find it userful, please comment if you find any issues with it.

// lets just make the email lowercase for the ALL CAPS people
$email = strtolower($_REQUEST["emailreal"]);

if (eregi("^[\.\+_a-z0-9-]+@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,6})$", $email) ) {
   // now do something cool!
}