PHP code to verify email address is valid

Sometimes, when filling out a form on a website, the user may enter an incorrect email address. This function can verify whether the email address is valid.

function is_validemail($email)
{
$check = 0;
if(filter_var($email,FILTER_VALIDATE_EMAIL))
{
$check = 1;
}
return $check;
}

Usage:

$email = "blog@open.com";
$check = is_validemail($email);
echo $check;
// If the output is 1, then email is valid.
?>

Email address, PHP