javascript - wp_head not working in plugin -

i've written simple plugin own use , i'm trying insert javascript head tag.

if use

add_action( 'init', 'add_to_head' );

then works, loads before jquery no good.

if use

add_action( 'wp_head', 'add_to_head' );

then nothing happens @ all! function i'm trying call.

function add_to_head() {?>  <script>alert("test");</script><?php }

there's no errors in console unless use add_action 'init' says jquery not defined (obviously).

update

if use add_action( 'get_footer', 'add_to_head' ); works! i'm not sure if right hook use.

use wp_footer hook, there nothing wrong use wp_footer hook.

<?php function add_to_head() {?>      <script>alert("test");</script><?php } add_action( 'wp_footer', 'add_to_head' ); ?>

JAV