# Callbacks (Browser Events) The Prism Web SDK dispatches browser events you can subscribe to from your host page. There are three core events: 1. `onPrismLoaded` - Fired when the SDK is ready and exposes a `PrismInstance` you can use to render the widget and provide runtime config (localization, asset overrides, etc.). 2. `onPrismScanComplete` - Fired when the recording finishes. Provides a `Blob` containing the captured video you can upload/store. 3. `onPrismStateChange` - Fired whenever the session state changes (e.g., LEVELING → POSITIONING → POSING → RECORDING → PROCESSING → FINISHED). Useful for analytics or UI orchestration. All events are dispatched on `window` using `CustomEvent` and can be listened to with `window.addEventListener`. --- ## onPrismLoaded Dispatched by the SDK once the `PrismInstance` is constructed. Payload shape - type: `CustomEvent<{ prism: PrismInstance }>` - source: `dispatchPrismLoaded(prism)` What you can do - Call `event.detail.prism.render(config)` to initialize the widget. - Provide runtime localization and/or asset overrides via the config. Example ```html ``` --- ## onPrismScanComplete Dispatched by the SDK when a scan finishes and a video blob is available. Payload shape - type: `CustomEvent<{ blob: Blob }>` - source: `dispatchScanComplete(blob)` Notes - The event won't fire if no blob is produced. Ensure recording was started and completed. - Use `URL.createObjectURL` for quick previews/downloads, or upload the `Blob` to your API. Examples ```html ``` --- ## onPrismStateChange Dispatched whenever the internal `PrismSessionState` changes. Payload shape - type: `CustomEvent<{ state: PrismSessionState }>` - source: `dispatchStateChange(state)` Common states you might observe - LEVELING, POSITIONING, POSING, RECORDING, PROCESSING, FINISHED (exact enum values are defined in `src/capture/session/prism-session-state.ts`). Examples ```html ``` --- ## Tips & Troubleshooting - Ensure your host page includes the SDK script and your event listeners are defined before the events fire (placing the listeners in the `` or before the script tag is ideal). - For localization overrides to take effect, they must be provided to `render` via `localization` and will be applied before the widget mounts. - Asset overrides require callers to resolve images through the SDK (e.g., using `resolveSvg('name')` in the UI). If you still see the default asset, ensure the component was updated to use the resolver. - For large blobs, consider streaming uploads or showing a progress indicator while uploading.