Question

I’m just guessing it’s possible so I tested and don’t work for me.
My Scenario here is :

function load_javascripts(){  
    wp_register_script( 'user-script', plugins_url( '/js/youtube-script.php', __FILE__ ), array( 'jquery' ) );
    wp_enqueue_script( 'user-script' );  
}
add_action('init','load_javascripts');

I am including a PHP file that has a majority of javascript in it (the include file)

Do you guys have any suggestion please ?

Answer 1

You should use wp_localize_script() to inject PHP variables in your javascript files.

PHP Example

 <?php
wp_enqueue_script( 'some_handle' );
$array_to_js = array( 'some_string' =>'hello world' );
wp_localize_script( 'some_handle', 'object_name', $array_to_js );
?> 

Javascript:

 <script>
alert(object_name.some_string); // alerts 'hello world'
</script>