> For the complete documentation index, see [llms.txt](https://docs.aurelia.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aurelia.io/developer-guides/error-messages/runtime-html/aur0769.md).

# AUR0769

## Error Message

`AUR0769: Failed to initialize the platform object. The host element's ownerDocument does not have a defaultView, did you create the host from a DOMParser and forget to call adoptNode()?`

## Description

Aurelia creates its browser platform from `host.ownerDocument.defaultView`. Documents created by `DOMParser` and `document.implementation.createHTMLDocument()` are detached document contexts, so their `defaultView` is `null`.

## Solution

Use a host owned by the active browser document. Adopt parsed content before configuring the application:

```typescript
const parsed = new DOMParser().parseFromString(
  '<main id="app"></main>',
  'text/html',
);
const host = document.adoptNode(parsed.querySelector<HTMLElement>('#app')!);
document.body.append(host);

const aurelia = new Aurelia().app({ host, component: MyApp });
await aurelia.start();
```

To copy the parsed subtree instead of moving it, replace the `adoptNode()` call with:

```typescript
const host = document.importNode(
  parsed.querySelector<HTMLElement>('#app')!,
  true,
);
```

A DOM-based test runner or rendering host can register its compatible `IPlatform` implementation in the application container.


---

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