content/test/data/fetch_later.html

<!doctype html>
<!--
  This page makes a fetchLater call, and posts message back to source.
-->
<title>FetchLater</title>
<script>
const PARAMS = new URL(location.href).searchParams;

const REQUEST_INIT = Object.assign({},
      PARAMS.has('activateAfter') ? {activateAfter: parseInt(PARAMS.get('activateAfter'), 10)} : null,
      PARAMS.has('method') ? {method: PARAMS.get('method')} : null,
    );

function postMessageBack(message) {
  if (window.opener) {
    window.opener.postMessage(message, '*');
  } else {
    parent.postMessage(message, '*');
  }
}

try {
  fetchLater('/beacon', REQUEST_INIT);
  postMessageBack({type: 'fetchLater.done'});
} catch (e) {
  postMessageBack({type: 'fetchLater.error', error: e});
}
</script>