wp_enqueue_script problem

First post to WordPress forums…

Any ideas on why this would work:

function add_header_scripts() {
	echo '<script src="https://localhost:8888/wp-content/themes/myTheme/myScript.js" type="text/javascript"></script>';
}

add_action('wp_head', 'add_header_scripts');

But this does not:

function add_header_scripts() {
	wp_enqueue_script('my_script', 'https://localhost:8888/wp-content/themes/myTheme/myScript.js');
}

add_action('wp_head', 'add_header_scripts');

Code is in functions.php.

I have also tried supplying values for all possible parameters of wp_enqueue_scripts including using null for $ver to avoid problems with appending version numbers to the script url.

Also, I know not to hardcode the url. I will use bloginfo once this problem is solved.

Thanks in advance!