Is there a way of checking the window's focus (not the document) from Javascript?

I see numerous questions along these lines, but they all require checking the document object. I’m trying to do this from a cross-domain iframe, so I don’t have access to top.document. Any way to do with with the window.top object?

UPDATE: see my answer below

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  • 2 Solutions collect form web for “Is there a way of checking the window's focus (not the document) from Javascript?”

    Pretty sure the answer is no. Such things are the responsibility of the document and not the window.

    I found this answer in another question, which uses window.onfocus and window.onblur. Unfortunately browser security seems to prevent attaching events to window.top.onfocus/blur….