Using add_action in function.php and limit to get_posts?

In functions.php

function map_header() {
echo ‘<script type=”text/javascript” src=”‘.get_bloginfo(‘stylesheet_directory’).’/js/gmap.js”></script>’;
echo ‘<script type=”text/javascript” src=”https://maps.google.com/maps/api/js?sensor=false”></script>&#8217;;
}
function map() {
echo ‘some html’;
add_action(‘wp_head’, ‘map_header’);
}
register_sidebar_widget(‘A map’, ‘map’);

How come this doesn’t work? It works when I place add_action outside of map() – but that’s not what I want. I only want to add the javascript if the widgets is being used.

Thank you