[Home](./index.md) > [@firebase/database](./database.md) > [OnDisconnect](./database.ondisconnect.md) > [set](./database.ondisconnect.set.md) ## OnDisconnect.set() method Ensures the data at this location is set to the specified value when the client is disconnected (due to closing the browser, navigating to a new page, or network issues). `set()` is especially useful for implementing "presence" systems, where a value should be changed or cleared when a user disconnects so that they appear "offline" to other users. See [Enabling Offline Capabilities in JavaScript](https://firebase.google.com/docs/database/web/offline-capabilities) for more information. Note that `onDisconnect` operations are only triggered once. If you want an operation to occur each time a disconnect occurs, you'll need to re-establish the `onDisconnect` operations each time. Signature: ```typescript set(value: unknown): Promise; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | value | unknown | The value to be written to this location on disconnect (can be an object, array, string, number, boolean, or null). | Returns: Promise<void> Resolves when synchronization to the Database is complete.