Document.adoptNode()

Document.adoptNode() transfers a node from another document into the method's document. The adopted node and its subtree is removed from its original document (if any), and its ownerDocument is changed to the current document. The node can then be inserted into the current document.

const importedNode = document.adoptNode(externalNode);

externalNode

The node from another document to be adopted.

The copied importedNode in the scope of the importing document.

After calling this method, importedNode and externalNode are the same object.

const iframe = document.querySelector('iframe');
const iframeImages = iframe.contentDocument.querySelectorAll('img');
const newParent = document.getElementById('images');

iframeImages.forEach(function(imgEl) {
  newParent.appendChild(document.adoptNode(imgEl));
});

Before they can be inserted into the current document, nodes from external documents should either be:

• cloned using document.importNode(); or
• adopted using document.adoptNode().

For more on the Node.ownerDocument issues, see the W3C DOM FAQ.

• document.importNode()