//Auto-update WooCommerce Cart when Quantity Changes
add_action( 'wp_footer', 'silva_cart_refresh_update_qty' ); 
 
function silva_cart_refresh_update_qty() { 
   if (is_cart()) { 
      ?> 
      <script type="text/javascript"> 
         jQuery('div.woocommerce').on('click', 'input.qty', function(){ 
            jQuery("[name='update_cart']").click();
         }); 
      </script> 
      <?php 
   } 
}