<!DOCTYPE html>
<script src="utils.js"></script>
<style>
  body, html {
    margin: 0;
    padding; 0;
    background-color: #bfb;
  }
</style>
<body>
  <div>Child frame</div>
</body>
<script>
  "use strict";
  let cancel_mousedown = false;

  window.addEventListener("load", () => {
      window.addEventListener("message", event => {
          let data = event.data;
          if (data.type == "cancel-mousedown")
              cancel_mousedown = data.param;
      });

      window.addEventListener("mousedown", e => {
          let msg = "not-canceled";
          if (cancel_mousedown) {
              e.preventDefault();
              msg = "canceled";
          }
          sendMessage(window.top, "mousedown", msg);
      });

      window.addEventListener("mouseup", e => sendMessage(window.top, "mouseup"));

      sendMessage(parent, "load");
  });
</script>
