add_action Not Printing

I have a plugin with the following code, but for the life of me it won’t print to the header. Ideas?


$wp_smoothscroll_url = get_bloginfo('wpurl') . "/";

function wp_smoothscroll() {

echo '
<script type="text/javascript" src="'.$wp_smoothscroll_url.'wp-content/plugins/smoothscroll/smoothscroll.js"></script>
';
}

add_action('wp_head', 'wp_smoothscroll');