Are hasOwnProperty () test results for DOM elements standardized?

Question

I was surprised to find that in the Firefox console:

> document.mozPointerLockElement
> null
> 'mozPointerLockElement' in document
> true
> document.hasOwnProperty('mozPointerLockElement')
> false

While in the test equivalent of the console, Chrome hasOwnProperty()returns true:

> document.webkitPointerLockElement
> null
> 'webkitPointerLockElement' in document
> true
> document.hasOwnProperty('webkitPointerLockElement')
> true

Does the HTML standard indicate which document properties should be straightforward and can be reliably checked with hasOwnProperty(), or are all such tests implementation-specific and not portable?

Answer 1

The HTML standard indicates which document properties should be straightforward and can be reliably checked with hasOwnProperty ()

, WebIDL . getter ( pointerLockElement readonly) document.prototype ( [Unforgeable]).

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