---
description: Watch for custom JS events in order to respond to Explo events in your app
---

# Custom JS Events

### What are Custom JS Events?

Explo uses the [CustomEvent](https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent) spec to fire our own events when certain things happen in the app that you might want to respond to in your app.

### How do I interact with Custom JS events?

You should be able to add an event listener in your app to respond to any of the available events listed on this page.

```javascript
const listener = (e) => {
  console.log(e.detail)
};

elem.addEventListener('EVENT_NAME', listener);
```

Just make sure you clean up the event listener when you're done with it.

```javascript
elem.removeEventListener(listener);
```

### Available Events

`updateVariableValue`

* Fires when a new value is selected for a variable.
* Returns `{ detail: { varName`: string`, newValue: any } }`
