Leaderboard

The main problem is that this $email_to = "email1@website.com", "email2@whatever.com"; isn't going to work. You can't just list multiple email address strings like that. But before that, the other problem is that you're manually trying to send emails. That's almost always bad: emails are hard, and doing it yourself is pretty much always going to go badly. Switch to a library like PHPMailer or SwiftMailer, which will not only be able to do emails properly but also make it easier to do things like add multiple recipients.