layer-change-1-ref.html
<!DOCTYPE html>
<html>
<head>
<body>
<iframe style="margin-top:100px; width:100%; height:600px;" src="layer-change-1-frame.html"></iframe>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<body>
<iframe style="margin-top:100px; width:100%; height:600px;" src="layer-change-1-frame.html"></iframe>
</body>
</html>