<!DOCTYPE html>
<script>
  document.addEventListener('DOMContentLoaded', async () => {
    await navigator.mediaDevices.getUserMedia({ 'audio': {} })
    const peer = new RTCPeerConnection({ 'iceServers': [{ 'urls': 'stun:23.21.150.121' }], 'peerIdentity': 'B' }, {})
    const stream = await navigator.mediaDevices.getUserMedia({ 'audio': {} })
    stream.getTracks().forEach((track) => peer.addTrack(track, stream))
    try { offer = await peer.createOffer({}) } catch (e) { }
    await peer.setRemoteDescription(offer)
  })
</script>
