php 模拟 http验证

<?php
  if (!isset($_SERVER['PHP_AUTH_USER'])) {
    header('WWW-Authenticate: Basic realm="My Realm"');
    header('HTTP/1.0 401 Unauthorized');
    echo '需要验证用户名、密码！';
    exit;
	
  } else if($_SERVER['PHP_AUTH_USER']=="admin" && $_SERVER['PHP_AUTH_PW']=="admin"){
    echo "<p>Hello {$_SERVER['PHP_AUTH_USER']}.</p>";
    echo "<p>登陆成功！You entered {$_SERVER['PHP_AUTH_PW']} as your password.</p>";
  
  } else  {
    header('WWW-Authenticate: Basic realm="My Realm"');
    header('HTTP/1.0 401 Unauthorized');
    echo ' 用户名、密码有误！';
    exit;
  
  }
?>