custom-script.js

<?php
function my_scripts_method() {
	wp_enqueue_script(
		'custom-script',
		get_template_directory_uri() . '/js/custom_script.js',
		array('jquery')
	);
}
add_action('wp_enqueue_scripts', 'my_scripts_method');
?>

custom-script.js
 jQuery(document).ready(function() {
   jQuery("table").each(function()
    // do stuff
     alert ("hello Holly");
   )};