# `Events['xr:start']`

> Contract 2.0.0 · package sha256 `a857eca95b35921109faf997094bb4192f12527d9d0fcd4be7e97f06425bad6e` · generated from `configurator-runtime.d.ts` by `services/onsite-scripter/scripts/build-contract-docs.mjs`; edit the source, not this file.

Property of [`Events`](Events.md) · labs, `@experimental` · since 2.0.0

```ts
'xr:start': {
  readonly presenter: 'webxr' | 'scene-viewer' | 'quick-look' | 'other';
  readonly experience: 'place' | 'try-on' | 'other';
};
```

Holostep's in-page AR or try-on showed its first picture: `experience` is 'place' (in-room AR)
or 'try-on', `presenter` the viewer that shows it, named as [`ActivateARReport.mode`](ActivateARReport.mode.md) and
`info().ar.modes` name it: 'webxr' for Holostep's in-page AR on either route (WebXR on
Android, the camera route on iOS), 'other' for try-on. Scene Viewer and Quick Look run outside
the page and fire no 'xr:start'.

## Fields

<a id="presenter"></a>
### `presenter`

```ts
readonly presenter: 'webxr' | 'scene-viewer' | 'quick-look' | 'other';
```

<a id="experience"></a>
### `experience`

```ts
readonly experience: 'place' | 'try-on' | 'other';
```

## Generic-API test (spec 3.1)

| Rule | Result |
| --- | --- |
| 1. Neutral name | pass: `xr:start` names no product |
| 2. A precedent | pass: [model-viewer canActivateAR and activateAR()](https://modelviewer.dev/docs/index.html#entrydocs-augmentedreality-methods-activateAR) (row `G66`); [XRSession.end()](https://developer.mozilla.org/en-US/docs/Web/API/XRSession/end) (row `G66`); [Navigator.share() (resolves when the share UI closes)](https://developer.mozilla.org/en-US/docs/Web/API/Navigator/share) (row `G66`) |
| 3. Two apps, or labs | labs (`@experimental` at a stable path, reached through `has()` or `supports()`): it graduates when a second app uses it; apps today: configurator-template, tryon-template |
| 4. The cheaper fix first | decided per need in Appendix B: rows `G66` at tier labs (a member only where no rule, data, asset or app code serves the need) |