***

id: 44994413-c3e3-480d-afcb-ee19f4ffde6c
title: 'on'
slug: /node/reference/video/client/on
description: on method for the Video Client class.
max-toc-depth: 3
----------------

### on

* **on**(`event`, `fn`)

Attaches an event handler to the specified event.

#### Parameters

| Name    | Type     | Description                                                                                                               |
| :------ | :------- | :------------------------------------------------------------------------------------------------------------------------ |
| `event` | `string` | Name of the event. See [Events](/docs/server-sdk/v3/node/reference/video/client/events) for the list of available events. |
| `fn`    | Function | An event handler.                                                                                                         |

#### Example

In the below example, we are listening for the `call.state` event and logging the current call state to the console.
This means this will be triggered every time the call state changes.

```js
call.on("call.state", (call) => {
    console.log("call state changed:", call.state);
});
```