Interface used for parent -> child node relationships.

• Read More on MDN
• WHATWG ParentNode Mixin

https://dom.spec.whatwg.org/#interface-parentnode

To convert nodes into a node, given nodes and document, run these steps:

1. Let node be null.

2. Replace each string in nodes with a new Text node whose data is the string and node document is document.

3. If nodes contains one node, set node to that node.

4. Otherwise, set node to a new DocumentFragment whose node document is document, and then append each node in nodes, if any, to it.

5. Return node.