## Click event `expressCheckoutElement.on(event: 'click', handler: function)`

The `click` event is triggered from an Express Checkout Element when the customer clicks a payment button. Use this event to configure the payment interface.

*   `event`
    The name of the event. In this case, `click`.
*   `handler`
    `handler(event) => void` is a **callback function** you provide that's called after the event is fired. After it's called, it passes an event object with the following properties:
    *   `elementType`
        The type of element the event is fired from, which is `expressCheckout` in this case.
    *   `expressPaymentType`
        The payment method the customer checks out with.
    *   `resolve`
        A function `resolve(payload) => void` that's called to show the payment interface. You must call this function within 1 second if you handle the `click` event.
    *   `allowedShippingCountries (deprecated)`
        _This parameter has been deprecated in favor of the `allowedShippingCountries` param on the [create](https://docs.stripe.com/js/elements_object/create_express_checkout_element.md#express_checkout_element_create-options-allowedShippingCountries) function._ By default, the Express Checkout Element allows all countries for shipping. You can specify which countries are allowed for shipping in the Express Checkout Element with a list of two-letter country codes.
    *   `applePay`
        Specify Apple Pay specific options. These are passed through to the Apple Pay API.
    *   `recurringPaymentRequest`
        Specify a request to set up a recurring payment. See the [Apple Pay documentation](https://developer.apple.com/documentation/apple_pay_on_the_web/applepayrecurringpaymentrequest) for more details.
        *   `paymentDescription`
        *   `managementURL`
        *   `regularBilling`
            *   `amount`
            *   `label`
            *   `recurringPaymentStartDate`
            *   `recurringPaymentEndDate`
            *   `recurringPaymentIntervalUnit`
            *   `recurringPaymentIntervalCount`
        *   `trialBilling`
            *   `amount`
            *   `label`
            *   `recurringPaymentStartDate`
            *   `recurringPaymentEndDate`
            *   `recurringPaymentIntervalUnit`
            *   `recurringPaymentIntervalCount`
        *   `billingAgreement`
    *   `deferredPaymentRequest`
        Specify a request to set up a deferred payment. See the [Apple Pay documentation](https://developer.apple.com/documentation/apple_pay_on_the_web/applepaydeferredpaymentrequest) for more details.
        *   `paymentDescription`
        *   `managementURL`
        *   `deferredBilling`
            *   `amount`
            *   `amountType`
                Indicates whether the billing amount is known at request time. When set to 'final', the Apple Pay payment sheet shows the configured amount.
            *