HTML5 also now includes an e-mail input type.
Try the e-mail example in firefox, chrome, or opera. It will not accept your entry without it being a valid e-mail.
<form action="http://www.example.org/subscribe.php">
<p>Please enter your email address:</p>
<input type="email" name="email" />
<input type="submit" value="Submit" />
</form>