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## CommonEventEmitter.on() method
Signature:
```typescript
on(event: EventType, handler: Handler): CommonEventEmitter;
```
## Parameters
| Parameter | Type | Description |
| --- | --- | --- |
| event | [EventType](./puppeteer.eventtype.md) | |
| handler | [Handler](./puppeteer.handler.md) | |
Returns:
[CommonEventEmitter](./puppeteer.commoneventemitter.md)