如何在不配置其他文件的情况下启用PHP会话

我将这段代码包含在我的php网页上

<?php
ini_set('session.use_cookies', 1);
ini_set('session.use_only_cookies', 1);
session_start();
?>

这里是PHP网页
a.php

<h1>Page AAAA</h1>
<a href="b.php?t=<? echo time(); ?>">go to page B</a>
<?php
   echo "<h2>CURRENT SESSION = ", $_SESSION['test'], "</h2>";
   $_SESSION['test'] = 'a';
   echo "<h2>AFTER CHANGE SESSION = ", $_SESSION['test'], "</h2>";
?>

b.php

<h1>Page BBBB</h1>
<a href="a.php?t=<? echo time(); ?>">go to page A</a>
<?php
   echo "<h2>CURRENT SESSION = ", $_SESSION['test'], "</h2>";
   $_SESSION['test'] = 'b';
   echo "<h2>AFTER CHANGE SESSION = ", $_SESSION['test'], "</h2>";
?>

，但它不工作。即使我在a.p p和b.p p之间切换，CURRENT SESSION也没有值

update我将这段代码包含在a.p p
echo "<h1>SESSION ID = ", session_id() , "</h1>";
结果
SESSION ID = fhhiilg08rl2ajtplqc9dbud43