<html>
  <head>
    <meta charset="utf-8" />
    <title>GetUserMedia from cross-origin iframe: the container document</title>
  </head>
  <body>
    <iframe
      id="iframe_no_allow"
      src="http://127.0.0.1:4245/assets/www/getusermedia_xorigin_iframe.html"
    ></iframe>
    <iframe
      id="iframe"
      allow="camera;microphone"
      src="http://127.0.0.1:4245/assets/www/getusermedia_xorigin_iframe.html"
    ></iframe>
    <script>
      "use strict";

      let iframeWindow;
      let generation = 1;

      async function Send(obj) {
        obj.gen = generation++;
        iframeWindow.postMessage(obj, "http://127.0.0.1:4245");
        while (true) {
          const {
            data: { gen, result },
          } = await new Promise(r => (window.onmessage = r));
          if (gen == obj.gen) {
            return result;
          }
        }
      }

      function Start(constraints) {
        if (iframeWindow) {
          return "iframe mode already decided";
        }
        iframeWindow = document.getElementById("iframe").contentWindow;
        return Send({ name: "start", constraints });
      }

      function StartNoAllow(constraints) {
        if (iframeWindow) {
          return "iframe mode already decided";
        }
        iframeWindow = document.getElementById("iframe_no_allow").contentWindow;
        return Send({ name: "start", constraints });
      }

      async function Stop() {
        const result = await Send({ name: "stop" });
        iframeWindow = undefined;
        return result;
      }
    </script>
  </body>
</html>
