Comment intégrer mon code paypal avec un input

 <script src="https://www.paypal.com/sdk/js?client-id=test¤cy=USD"></script>

    <!-- Set up a container element for the button -->
    <div id="paypal-button-container"></div>

    <script>
      paypal.Buttons({

        // Sets up the transaction when a payment button is clicked
        createOrder: function(data, actions) {
          return actions.order.create({
            purchase_units: [{
              amount: {
                value: '77.44' // Can reference variables or functions. Example: `value: document.getElementById('...').value`
              }
            }]
          });
        },

        // Finalize the transaction after payer approval
        onApprove: function(data, actions) {
          return actions.order.capture().then(function(orderData) {
            // Successful capture! For dev/demo purposes:
                console.log('Capture result', orderData, JSON.stringify(orderData, null, 2));
                var transaction = orderData.purchase_units[0].payments.captures[0];
                alert('Transaction '+ transaction.status + ': ' + transaction.id + '\n\nSee console for all available details');

            // When ready to go live, remove the alert and show a success message within this page. For example:
            // var element = document.getElementById('paypal-button-container');
            // element.innerHTML = '';
            // element.innerHTML = '<h3>Thank you for your payment!</h3>';
            // Or go to another URL:  actions.redirect('thank_you.html');
          });
        }
      }).render('#paypal-button-container');

    </script>

 amount: {
               value:  document.querySelector('amount').value
              }

 amount: {
                value: '77.44' // Can reference variables or functions. Example: `value: document.getElementById('...').value`
              }

<div>*Prix total: <b><span class="total-panier" id="prix_total" >9.00</span> euros</b></div>