Hmm. window.close() already handles this use case. But document.close() should not blow away event listeners (see spec).

This seems wrong to me.

Event listeners added to a window are in fact cleared and the problem doesn't exist. However we can see a comment in close function in document-impl.js:
// Set the readyState to 'complete' once all resources are loaded.
// As a side-effect the document's load-event will be dispatched.
...
ev.initEvent("DOMContentLoaded", false, false);
this.dispatchEvent(ev);

Is emmiting this event defined by spec or is it some kind of jsdom hack? Maybe we should consider removing only DOMContentLoaded from eventListeners?

document.close() should definitely never remove any event listeners. If you are trying to close the window and stop event listeners, use window.close(), not document.close().

It sounds like it might be a separate issue where document.close() should not be what fires the DOMContentLoaded event. Instead, the parser probably should.

I call window.close which in turn calls document.close which causes DOMContentLoaded to be fired. If proposed solution to this problem is incorrect what should be done next? Shall I create an issue to track this bug?

Yes. window.close() needs to clear the event handlers; if it is not doing so then something is wrong. But document.close() should not clear event handlers.

I checked window.close() function and I think I found the bug. I have provided a new solution. What do you think about it?

Oh, wow, excellent find, thank you! Yes, I'll include this in the next release (probably this weekend).

Great, I'm glad I could help.

Merged as 868560b; thanks!