# callbacks.onPrint

Part of [Callbacks](https://kernstra.com/docs/web-sdk/config/callbacks) in the Kernstra Web SDK 1.0.0 configuration reference.

- Type: `() => void`
- Page: https://kernstra.com/docs/web-sdk/config/callbacks/onprint

Takes over the toolbar Print button and Ctrl / ⌘ + P; not called when the document forbids printing. When set, the SDK's Print dialog does not run; print with [`viewer.print({ pages })`](https://kernstra.com/docs/web-sdk/api/pdfviewer/print).

Web page: https://kernstra.com/docs/web-sdk/config/callbacks/onprint