# Native handling of JavaScript events
You can handle events from in-app message interactions natively within your application by completing the following steps:
- [Implement and assign a `Messaging Delegate`](#implement-and-assign-a-messaging-delegate)
- [Register a JavaScript handler for your In-App Message](#register-a-javascript-handler-for-your-in-app-message)
- [Post the JavaScript message from your In-App Message](#post-the-javascript-message-from-your-in-app-message)
## Implement and assign a `Messaging Delegate`
To register a JavaScript event handler with a Message object, you will first need to implement and set a MessagingDelegate.
Please read the [documentation](../README.md/#programmatically-control-the-display-of-in-app-messages) for more detailed instructions on implementing and using a MessagingDelegate.
## Register a JavaScript handler for your In-App Message
In the `onShow` function of `MessagingDelegate`, call `handleJavascriptMessage(handlerName: string, handler: (content: string) => void)` to register your handler.
The name of the message you intend to pass from the JavaScript side should be specified in the first parameter.
### Example
```typescript
Messaging.setMessagingDelegate({
onShow: msg => {
console.log('show', msg);
msg.handleJavascriptMessage(
'myInappCallback',
(content) => {
console.log('Received webview content:', content);
}
);
}
});
```
## Post the JavaScript message from your In-App Message
Now that the in-app message has been displayed, the final step is to post the JavaScript message.
Continuing from the previous example, the developer is going to post the `myInappCallback` message from their HTML, which will in turn call the handler previously configured:
```html
```
Note: (The above HTML is not representative of a valid in-app message, and is intended only to demonstrate how to post the JavaScript message).
When the user clicks the button inside of this in-app message, the handler configured in the previous step will be called. The handler will send an Experience Event tracking the interaction, and print the following message to the console:
```bash
JavaScript body passed to react native callback: callbacks are cool!
```
# Execute JavaScript methods from native code
You can execute JavaScript in an in-app message from native code by completing the following steps:
- [Implement and assign a `Messaging Delegate`](#implement-and-assign-a-messaging-delegate-1)
- [Call the Javascript method](#call-the-javascript-method)
## Implement and assign a `Messaging Delegate`
To register a JavaScript event handler with a Message object, you will first need to implement and set a MessagingDelegate.
Please read the [documentation](../README.md/#programmatically-control-the-display-of-in-app-messages) for more detailed instructions on implementing and using a MessagingDelegate.
## Call the JavaScript method
In the `onShow` function of `MessagingDelegate`, call `evaluateJavascript(javascriptString: string, callback: (result: string) => void)`.
### Example
```typescript
Messaging.setMessagingDelegate({
onShow: msg => {
console.log('show', msg);
msg.evaluateJavascript(
"(function() {console.log('my test'); return 'some result';})();",
(result: string) => {
console.log('Result:', result);
}
);
}
});
```