You’re using an invalid action: add_action(‘wp_enqueue_script’, ‘run_js_script’); The correct action is wp_enqueue_scripts (plural), not wp_enqueue_script (singular). Use this instead: add_action(‘wp_enqueue_scripts’, ‘run_js_script’); Edit Same problem here: add_action(‘wp_register_script’, ‘register_script’); Just hook it into wp_enqueue_scripts for simplicity: add_action(‘wp_enqueue_scripts’, ‘register_script’); Actually, two better options: Put your wp_register_script() call in the same run_js_script callback as your wp_enqueue_script() call. Eliminate wp_register_script() … Read more