php validate email function

PHP

$email = "mytest@email.com"; // this should be valid as it contains an @ and a . and an extention.
$email_non_valid = "xxx";

// use this if you have a form with post back and an email element
// $email = test_input($_POST["email"]);

  // validate an email address returns true or false 
  function validate_email($email) {
    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
      return false;
    } else {
      return true;
    }
  }



/* this should return true */
if (!validate_email($email)) {
	echo $email_valid = "The email address $email is <b>NOT</b> valid<br>";
} else {
	echo $email_valid = "The email address $email is valid<br>";
}

/* this should return false */
if (!validate_email($email_non_valid)) {
	echo $email_valid = "The email address $email_non_valid is <b>NOT</b> valid<br>";
} else {
	echo $email_valid = "The email address $email_non_valid is valid<br>";
}