event.target document

Assuming a number of document are nested with a click event handler defined 
in  one of the parent documents

how do you figure out the document in which a click event actually occurred?

    As far as I can tell event.target.ownerDocument will return the document 
where the event handler is

but not the document  containing the node generating the event

Is there any thing like

        event.target.targetDocument

or a work around?

PS sorry for cross post