1）PHP Version 4.0.6，register_globals = On；
2）page1.php中：
<?
session_start();
session_register ("test1");
session_register ("test2");
$HTTP_SESSION_VARS["test1"] = "1";
$HTTP_SESSION_VARS["test2"] = "2";
echo "A=".sizeof($HTTP_SESSION_VARS);
echo "<html>\n";
echo "<body>\n";
echo "<form name=form_1 method=post action='page2.php'>\n";
echo "<input type=submit value='SUBMIT'>\n";
echo "</body>\n";
echo "</html>\n";
?>
输出显示A=2
3）page2.pho：
<?
session_start();
echo "A=".sizeof($HTTP_SESSION_VARS);
?>
从page1.php点SUBMIT后，显示A=0
4）请问这是�