# Communicating with external sites via Iframe

Let's say you have a website or application embedded in the UI Bakery Iframe component and you need to communicate with it - send or receive data. You can easily do this using the *JavaScript* `postMessage` *function*.

Follow the instruction below for details:

1. Give your Iframe component a *unique name* to send the data. \
   This name will be added as a component class allowing you to query it with JavaScript.
2. Create a **JavaScript Code** action and specify the following code to query the Iframe and send messages to it:

```javascript
const iframe = document.querySelector('.uniqueName > iframe').contentWindow;
iframe.postMessage('message', { foo: 'bar' })
```

<figure><img src="https://837703843-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FUX6zPRMFFK0yrTghj7cY%2Fuploads%2FPyHNT3g9f3NhnkCXwEO1%2FCleanShot%202025-02-18%20at%2015.35.33%402x-min-min.png?alt=media&#x26;token=da84685c-01ab-4a65-b3a3-8743ad0e8e9c" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
Depending on the receiving app configuration, `postMessage` may require [additional setup](https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage#security_concerns).
{% endhint %}

***

Similarly, you can also *subscribe to events from the Iframe* via a **JavaScript Code** action step with the following code:

```javascript
const iframe = document.querySelector('.uniqueName > iframe').contentWindow;
iframe.on('message', (data) => {
  console.log(data);
});
```

And you need to assign this action to the *On Page Load* trigger to bind the listener to the new messages when the app loads.


---

# Agent Instructions: 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:

```
GET https://docs.uibakery.io/how-tos/custom-code/communicating-through-the-iframe-component.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.