<html>
<body>
<script>

var iframe = document.createElement('iframe');
iframe.setAttribute("mozbrowser", "true");

iframe.addEventListener('mozbrowsershowmodalprompt', function(e) {
  if (e.detail.message == 'child:ready') {
    setTimeout(function() {
      iframe.setVisible(false);
      iframe.setVisible(true);
      setTimeout(function() {
        alert('parent:finish');
      }, 0);
    }, 0);
  }
});

document.body.appendChild(iframe);
iframe.src = 'file_browserElement_SetVisibleFrames_Inner.html?child';

</script>
</body>
</html>