[Home](./index.md) > [puppeteer](./puppeteer.md) > [Page](./puppeteer.page.md) > [once](./puppeteer.page.once.md) ## Page.once() method Signature: ```typescript once(eventName: K, handler: (event: PageEventObject[K]) => void): EventEmitter; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | eventName | K | | | handler | (event: [PageEventObject](./puppeteer.pageeventobject.md)\[K\]) => void | | Returns: [EventEmitter](./puppeteer.eventemitter.md)