The DocumentFragment.querySelectorAll() method returns a NodeList of elements within the DocumentFragment (using depth-first pre-order traversal of the document's nodes) that matches the specified group of selectors.
If the selectors specified in parameter are invalid a DOMException with a SYNTAX_ERR value is raised.
querySelectorAll(selectors)
A non-live NodeList containing one Element object for each element that matches at least one of the specified selectors or an empty NodeList in case of no matches.
This example returns a list of all div elements within the DocumentFragment with a class of either "note" or "alert":
const matches = documentfrag.querySelectorAll("div.note, div.alert");