javascript Node firstChild, lastChild

Return a reference to the first or last child node (respectively) of the current element node. Most commonly, these child nodes are text nodes nested inside an element. For a simple element containing only one text node, both properties return a reference to the same text node. More complex constructions, such as tr elements, can have other element nodes (td elements) as their child nodes, but some browsers may turn source code carriage returns between elements into text nodes. Therefore, it's a good idea to validate the type of node returned by either property before acting on it.