Trigger a javascript function when a WooCommerce order comes in processing status

In WooCommerce, When customer place an order after payment, it's redirected to "Order received" (Thankyou) page, that is the only moment where you can trigger javascript function for a "processing" order status:

1). Enqueuing a Js File

add_action('wp_enqueue_scripts', 'order_received_enqueue_js_script');
function order_received_enqueue_js_script() {
    // Only on order received" (thankyou)
    if( ! is_wc_endpoint_url('order-received') )
        return;

    $order_id = absint( get_query_var('order-received') ); // Get the order ID

    $order = wc_get_order( $order_id ); // Get the WC_Order Object

    // Only for processing orders
    if ( ! is_a( $order, 'WC_Order') || ! $order->has_status( 'processing' ) ) {
        return;
    }

    wp_enqueue_script( 
        'my-java', // Handle
        get_stylesheet_directory_uri() . '/js/custom.js?V=2020.08.01v12', // URL for child or parent themes
        array( 'jquery' ), // Dependencies
        false, // Version
        true // In footer
    );
}

2). Calling a javascript function

add_action('wp_footer', 'order_received_js_script');
function order_received_js_script() {
    // Only on order received" (thankyou)
    if( ! is_wc_endpoint_url('order-received') )
        return; // Exit

    $order_id = absint( get_query_var('order-received') ); // Get the order ID

    if( get_post_type( $order_id ) !== 'shop_order' ) {
        Return; // Exit
    }

    $order = wc_get_order( $order_id ); // Get the WC_Order Object

    // Only for processing orders
    if ( method_exists( $order, 'has_status') && ! $order->has_status( 'processing' ) ) {
        return; // Exit
    }

    ?>
    <script>
    // Once DOM is loaded
    jQuery( function($) { 
        // Trigger a function (example)
        myJsFunctionName('order-received', 'processing', {
            'order_id':       '<?php echo $order->get_order_id(); ?>',
            'order_key':      '<?php echo $order->get_order_key(); ?>',
            'transaction_id': '<?php echo $order->get_order_id(); ?>',
            'total':          '<?php echo $order->get_total(); ?>',
            'currency':       '<?php echo $order->get_currency(); ?>'
        });
    });
    </script>
    <?php
}

This kind of example is used by tracking scripts for example, like for GooGle Analytics…

You can use the “wp_footer” action in PHP to output a JS function declaration like so:

function my_php_function() {
echo '<script>
function myFunction() {
  console.log("myFunction() was called.");
}
</script>';
}
add_action('wp_footer', 'my_php_function');

https://wordpress.org/support/topic/calling-a-function-from-functions-php/

refer this site - Woocommerce checkout page hooks

example-

 function ts_review_order_before_submit(){
   echo'<button onclick="js_function()" id="function" > JS 
          function 
        </button>'
 }