> For the complete documentation index, see [llms.txt](https://docs.hyperswitch.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hyperswitch.io/integration-guide/payment-experience/readme-1/custom-events-1.md).

# Custom Events

### Listen to Expiry Date event

This event is triggered when the expiry date changes. Merchants can listen to this event and implement checks and validations based on the received value.\\

```javascript
// CheckoutForm.js
window.addEventListener("message", (ev) => {
    // Collecting Expiry Date
    if (ev.data.expiryDate) {
      console.log("Expiry date => ", ev.data.expiryDate);
    }
  });
```

### Listen to Payment Method event

Merchants can listen to the Payment Method Info event to receive real-time updates when a customer selects or changes their payment method. This event provides essential details about the selected payment method, allowing merchants to implement custom checks, validations, or UI updates based on the received data.

For card payments, the event will include additional details such as:

* **Card Brand**: The card network, e.g., **Visa, Mastercard,** etc.

```javascript
// CheckoutForm.js
window.addEventListener("message", (ev) => {
    // Collecting Expiry Date
    if (ev.data.expiryDate) {
      console.log("Expiry date => ", ev.data.expiryDate);
    }
  });
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.hyperswitch.io/integration-guide/payment-experience/readme-1/custom-events-1.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.