为什么WordPress中的自定义表单不会重定向到指定的操作？

When submitting the following custom form in WordPress, the system sends to index.php instead of the php page specified in action. Why is this happening and how can it be resolved?

Code:

<form action="<?php bloginfo('template_url'); ?>/signincode.php" method="POST" id="form2">

Are you using a paren and child theme? Instead of bloginfo('template_url') try

<?php echo get_template_directory_uri(); ?>

http://codex.wordpress.org/Function_Reference/get_template_directory_uri