v154 · targetAddressSpace

Does this browser read it?

Because the option is a dictionary member, the answer is a fact rather than an inference: define it as a getter and see whether the constructor touches it. No connection, no permission prompt, no user agent string.

Probe the member

Running…

Each member of WebSocketInit, and what the constructor did with it
memberread by the constructor?notes

Accepted values

What each value does when passed
valueoutcomemeaning

The probe sockets are closed immediately. An invalid enum value should be a TypeError at construction — before any network activity — which is what makes a typo a bug you find rather than a permission you silently never get.

see also