Since the W3C WebSocket API was clarified to reflect that onmessage is only called during the OPEN readyState (14474 - Make it possible to close a connection in such a manner that all subsequent events are suppressed), there are corresponding editorial changes required in Section 9 Garbage Collection:

A WebSocket object whose readyState attribute's value was set to OPEN (1) or CLOSING (2) as of the last time the event loop started executing a task must not be garbage collected if there are any event listeners registered for message events, error, or close events.

should differentiate between OPEN and CLOSING:

A WebSocket object whose readyState attribute's value was set to OPEN (1) as of the last time the event loop started executing a task must not be garbage collected if there are any event listeners registered for message events, error, or close events.

A WebSocket object whose readyState attribute's value was set to CLOSING (2) as of the last time the event loop started executing a task must not be garbage collected if there are any event listeners registered for error or close events.