"/project6/z/class/Dtable/ex_change.php"
我们通过POST方式传递过来的ID有：
Notice: Undefined index: ma in C:\xampp\htdocs\BeiDou_website\z\class\Dtable\ex_change.php on line 18
Notice: Undefined index: ma in C:\xampp\htdocs\BeiDou_website\z\class\Dtable\ex_change.php on line 22