comment_form_top action-hook . WP 3.0.0
Fires at the top of the comment form, inside the form tag.
Usage
add_action( 'comment_form_top', 'action_function_name_4398' );
function action_function_name_4398(){
// action...
}Where the hook is called
comment_form_top
wp-includes/comment-template.php 2400
do_action( 'comment_form_top' );