How to display alert and redirect?

Question

PHP

How to make first echo in which js code (in my case, alert with information about incorrect login or passwords) and then redirect to the authorization page (login.php)
Tried like this but an error

cry

if($login == $adminLogin AND $pass == $adminPass)
{
  $_SESSION['admin'] = true;
  header("Location: index.php");
  exit;
}
else
{
  echo '<script>alert("Логин и/или пароль неверны!");</script>';
  header("Location: login.php");
  exit;
}

Answer 1

make a redirect with js'om after the alert.
PHP generally rests here.