getting a js file for one page

You’re registering/enqueueing your script wrong. You should register/enqueue in your theme’s functions.php file instead of inside the header/page.

Also, you need to use your theme’s directory … which will be along the lines of mydomain.com/wp-content/themes/BLANK-Theme/js/SliderViewer-1.2.js.

Use this code in functions.php:

function my_scripts_enqueue_method() {
    wp_enqueue_script(
        'SliderViewer',
        get_template_directory_uri() . '/js/SliderViewer-1.2.js'
    );
}
add_action( 'wp_enqueue_scripts', 'my_scripts_enqueue_method' );

This will enqueue and register your script, and ensure that you’re using the appropriate directory for your theme in the process.