New To PHP and, I am currently attempting to create a plug in that creates an alert box every time the quantity in a cart is changed. So far I have successfully implemented updating the cart automatically, but I am having trouble determining how to create an alert box on update each time that references the new cart total. Any advice would be appreciated.

TLDR: Creating a plug in that will display an alert box when you change the quantity of an item in the cart with the following text:

“You just changed the quantity of ABC to 2”, where ABC is the SKU name, and 2 is the current (new) quantity of the item.

<?php
/**
 * Plugin Name: Order Check 2
**/
add_action( 'wp_footer', 'cart_update_qty_script', 'persistent_cart_update');

function persistent_cart_update() {
    foreach ( WC()->cart->get_cart() as $cart_item ) {
        // gets the cart item quantity
        $quantity           = $cart_item['quantity'];}
    }
function phpAlert($msg) {
    echo '<script type="text/javascript">alert("' . $msg . '")</script>';
}
function cart_update_qty_script() {
    if (is_cart()) :
    ?>
    <script>
         jQuery('div.woocommerce').on('change', '.qty', function(){
        jQuery("[name="update_cart"]").prop("disabled", false);
        jQuery("[name="update_cart"]").trigger("click"); 
    });
    
    </script>
<?php phpAlert(   "Your have changed the quantity of sweatshirts to " .$quantity.".");  ?>
   
    <?php
    endif;
}

?>