Node.prototype.ownerDocument
While it is not met, but later is unable to obtain direct document node may occur, then you can get to it by any node.
document.scripts[0].ownerDocument === document; // true document.ownerDocument; // null
Node.prototype.ownerDocument
While it is not met, but later is unable to obtain direct document node may occur, then you can get to it by any node.
document.scripts[0].ownerDocument === document; // true document.ownerDocument; // null