FE: Create stablecoin collection sub-account link

1. Embedding

Embed the page by loading the URL returned by the server in an iframe.

2. Close event: postMessage contract

When the user clicks the close button inside the collect page, the iframe sends a postMessage to the parent window so the parent can hide the iframe, close a modal, or perform other actions.

2.1 Message payload

Field	Type	Description
`type`	string	Always `'MERCHANT_COLLECT_CLOSED'`; use this to identify the close event
`source`	string	Always `'merchant-collect'`; identifies the sending page

Example:

{
  "type": "MERCHANT_COLLECT_CLOSED",
  "source": "merchant-collect"
}

2.2 When the message is sent

The message is sent only when the page is inside an iframe (i.e. window.parent !== window).

It is sent to window.parent with targetOrigin set to '*'.

3. Parent page: how to listen

3.1 Plain JavaScript

3.2 Validate origin (recommended)

To avoid accepting messages from other origins, validate event.origin against an allowlist:

FE: Create stablecoin collection sub-account link

1. Embedding#

2. Close event: postMessage contract#

2.1 Message payload#

2.2 When the message is sent#

3. Parent page: how to listen#

3.1 Plain JavaScript#