chromium/third_party/blink/web_tests/http/tests/inspector-protocol/resources/fledge_join.html

<script>
iterLimit = 2;
if (location.search !== '')
  iterLimit = parseInt(location.search.substr(1));
for (var i = 0; i < iterLimit; ++i) {
  navigator.joinAdInterestGroup({
    name: i,
    owner: "https://a.test:8443/",
    biddingLogicURL: "https://a.test:8443/inspector-protocol/resources/fledge_bidding_logic.js.php",
    ads: [{
      renderURL: 'https://example.com/render' + i,
      metadata: {ad: 'metadata', here: [1, 2, 3]}
    }]
  }, 3000);
}
</script>