成功交易后的Paypal将数据存储到MySQL

I have followed the "Basic Integration" from Paypal here : PayPal Checkout

I have tested it with sandbox "buyer" and "facilator" transactions works fine and button too.

How could I make the Paypal javascript below send the POST value I already have on the page to another page PHP if success for example ?

Here is Paypal button code :

        <div id="paypal-button-container" align="center"></div>

      <script>
        paypal.Buttons({
            style: {
    layout:  'vertical',
    color:   'blue',
    shape:   'rect',
    label:   'paypal',
  },
    createOrder: function(data, actions) {
      return actions.order.create({
        purchase_units: [{
          amount: {
            value: '<?php echo $total_total_euro_photo ?>'
          }
        }]
      });
    },
    onApprove: function(data, actions) {
      return actions.order.capture().then(function(details) {
        alert('Transaction completed by ' + details.payer.name.given_name);
        // Call your server to save the transaction
        return fetch('/paypal-transaction-complete', {
          method: 'post',
          headers: {
            'content-type': 'application/json'
          },
          body: JSON.stringify({
            orderID: data.orderID
          })
        });
      });
    }
  }).render('#paypal-button-container');
      </script>

In the approve function it is writed // Call your server to save the transaction Can I put there some code that is execute in background exemple savecommande.php?somevalue:anothervalue:etc ? If it could submit the form on the current page it would works too after transaction is successfull.

Some help would be very much appriciate.