Add elements to the set of matched elements.

Add the previous set of elements on the stack to the current set, optionally filtered by a selector.

Add the previous set of elements on the stack to the current set.

Get the children of each element in the set of matched elements, including text and comment nodes.

End the most recent filtering operation in the current chain and return the set of matched elements to its previous state.

Remove elements from the set of matched elements.