How can I check for an open URL in another window?

Question

This is a follow up to my last question Open a window if the window does not already exist Essentially, I am now keeping a list of all the window references that have been o

Answer 1

No, this would be a security/privacy issue.

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Since others have brought up the ownership/cookie state storage: this only works if you are also the same document which opened the window, i.e. in the scenario where the user shuts the window down and reopens then these references are indeed lost (and even if you stored them, you wouldn't have permission to close them any more)