为什么我输入了refresh不会跳转？请教大神支招！

Question

<?php

header('content-type:text/html;charset=utf-8');

if(isset($_post['提交'])){

$username = $_post['username'];

$password = $_post['password'];

if(empty($username)||empty($password)){

header('Refresh:3;url=login.php');

echo '用户名密码不能为空';

exit;

}

}else{

include_once 'templates/login.html';

}

?>

Answer 1

找出问题了，是php的变量没注意区分大小写