Playground doesn't allow-forms

[carnoxen]

Summary

The result is not operating.

URL

https://developer.mozilla.org/en-US/docs/Web/API/HTMLFormElement/submit_event

Reproduction steps

1. Type to text field.
2. Click submit button.
3. There is no printing but error message in console.

Expected behavior

The result can print text.

Actual behavior

1. Type to text field.
2. Click submit button.
3. The text is printed under the submit button.

Device

Desktop

Browser

Edge

Browser version

Stable

Operating system

Windows

Screenshot

Anything else?

No response

Validations

• I have read the Community Participation Guidelines.
• I have verified that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• I have checked that this is a concrete bug. For Q&A open a GitHub Discussion.

[LeoMcA]

@fiji-flo is there a security reason we don't add allow-forms to playground examples in content, but we do add it in the playground itself (where this example works as intended)?