经测试代码如下：
<?PHP
/**
* HTTP认证
*
* @param
* @arrange (512.笔记) jb51.cc
**/
// input user/pass below
$username = "INSERT YOUR DESIRED USERNAME HERE";
$password = "INSERT YOUR DESIRED PASSWORD HERE";
// password protect via http
if(!(isset($_SERVER['PHP_AUTH_USER']) &&
isset($_SERVER['PHP_AUTH_PW']) &&
$_SERVER['PHP_AUTH_USER'] == $username &&
$_SERVER['PHP_AUTH_PW'] == $password)){
header('WWW-Authenticate: Basic realm="Secured Area"');
header('Status: 401 Unauthorized');
}else{
/*** 来自：编程之家 jb51.cc（jb51.cc） ***/
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<Meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Page Name jb51.cc</title>
</head>
<body>
<!-- // html -->
</body>
</html>
<?PHP } ?>