Enqueue Header Menu Script

functions.php

/**
 * Register and Enqueue Header Navigation Menu Script
 * 
 * @author Brad Potter
 * 
 * @link http://www.bradpotter.com
 */
function gst_headermenu_script() {
  	
	wp_register_script( 'header-menu', get_stylesheet_directory_uri() . '/js/headermenu.js', array('jquery'), '1.0.0', false );
	wp_enqueue_script( 'header-menu' );

 }
add_action('wp_enqueue_scripts', 'gst_headermenu_script');