<?php    //unset($_SERVER['PHP_AUTH_USER']);    $strAuthUser= $_SERVER['PHP_AUTH_USER'];          $strAuthPass= $_SERVER['PHP_AUTH_PW']; if (! ($strAuthUser == "a" && $strAuthPass == "a")) {  header('WWW-Authenticate: Basic realm="wly"');  header('HTTP/1.0 401 Unauthorized');  echo "用戶驗證!!";  exit; } else {  echo "驗證通過";    header("location:http://www.baidu.com");  //unset($_SERVER['PHP_AUTH_USER']);   }?>

<?php  function authenticate_user() {    header('WWW-Authenticate: Basic realm="Secret Stash"');   header("HTTP/1.0 401 Unauthorized");    exit;  }   if (! isset($_SERVER['PHP_AUTH_USER'])) {    authenticate_user();  } else {    mysql_pconnect("localhost","authenticator","secret") or die("Can't connect to database server!");    mysql_select_db("java2s") or die("Can't select authentication database!");    $query = "SELECT username, pswd FROM user WHERE username='$_SERVER[PHP_AUTH_USER]' AND pswd=MD5('$_SERVER[PHP_AUTH_PW]')";     $result = mysql_query($query);     // If nothing was found, reprompt the user for the login information.    if (mysql_num_rows($result) == 0) {     authenticate_user();    }  } ?>