firefox/docshell/test/browser/file_onbeforeunload_nested_outer.html

<body>
<iframe src="http://example.org/browser/docshell/test/browser/file_onbeforeunload_nested_inner.html"></iframe>
</body>
	`<body>`
	`<iframe src="http://example.org/browser/docshell/test/browser/file_onbeforeunload_nested_inner.html"></iframe>`
	`</body>`