<form method="post" class="paypal-button form" target="_top" action="https://securepayments.sandbox.paypal.com/webapps/HostedSoleSolutionApp/webflow/sparta/hostedSoleSolutionProcess">
                                    <div class="form-group">
                                        <label for="subtotal">Crediti da aggiungere:</label>
                                        <select id="subtotal" name="subtotal" class="form-control">
                                            <option value="5.0">5.0 (IVA esclusa)</option>
                                            <option value="10.0">10.0 (IVA esclusa)</option>
                                            <option value="1000.0">1000.0 (IVA esclusa)</option>
                                        </select>
                                    </div>

                                    <input type="hidden" name="tax" value="22.0">
                                    <input type="hidden" name="notify_url" value="https://my.toolboxoffice.it:9443/@@acquista_crediti_view?user=keul&amp;group=Acme">
                                    <input type="hidden" name="return" value="https://my.toolboxoffice.it:9443/thank_you">
                                    <input type="hidden" name="cancel_return" value="https://my.toolboxoffice.it:9443/cancelled">

                                    <input type="hidden" name="currency_code" value="EUR">
                                    <input type="hidden" name="lc" value="IT">
                                    <input type="hidden" name="button" value="buynow">
                                    <input type="hidden" name="item_name" value="Ricarica Crediti">
                                    <input type="hidden" name="quantity" value="1">

                                    <input type="hidden" name="business" value="UMDR5P3TWG4VQ">
                                    <input type="hidden" name="bn" value="Toolbox_BuyNow_WPS_IT">
                                    <input type="hidden" name="paymentaction" value="sale">
                                    <div class="btn-group">
                                        <button type="submit" class="paypal-button large btn btn-default">Acquista</button>
                                    </div>
                                    <div class="btn-group">
                                        <a href="https://my.toolboxoffice.it:9443:9443/cancelled" class="btn btn-default">Annulla</a>
                                    </div>
                                </form>