[Home](./index.md) > [@firebase/messaging](./messaging.md) > [onMessage](./messaging.onmessage.md) ## onMessage() function When a push message is received and the user is currently on a page for your origin, the message is passed to the page and an `onMessage()` event is dispatched with the payload of the push message. Signature: ```typescript export declare function onMessage(messaging: FirebaseMessaging, nextOrObserver: NextFn | Observer): Unsubscribe; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | messaging | [FirebaseMessaging](./messaging.firebasemessaging.md) | The FirebaseMessaging instance. | | nextOrObserver | NextFn<[MessagePayload](./messaging.messagepayload.md)> \| Observer<[MessagePayload](./messaging.messagepayload.md)> | This function, or observer object with next defined, is called when a message is received and the user is currently viewing your page. | Returns: Unsubscribe To stop listening for messages execute this returned function.