Appendix – postMessage Patterns

<button id="btn-turbo">Turbo</button>
<button id="btn-highlow">High/Low</button>
<iframe id="ts-game" src="…"></iframe>
<script>
  const iframe = document.getElementById('ts-game');
  document.getElementById('btn-turbo').addEventListener('click', () => {
    iframe.contentWindow.postMessage({ type: 'gameSelect', payload: 'gameSelectedTurbo' }, 'https://trading.<yourbrand>.com');
  });
  document.getElementById('btn-highlow').addEventListener('click', () => {
    iframe.contentWindow.postMessage({ type: 'gameSelect', payload: 'gameSelectedHL' }, 'https://trading.<yourbrand>.com');
  });
  window.addEventListener('message', (event) => {
    // Optional: handle messages back from the iFrame
    // Validate origin: if (event.origin !== 'https://trading.<yourbrand>.com') return;
  });
</script>

const frameA = document.getElementById('frameA').contentWindow;
const frameB = document.getElementById('frameB').contentWindow;
window.addEventListener('message', (event) => {
  const data = event.data;
  // if (event.origin !== 'https://trading.<yourbrand>