FirstChild
firstChild is a standard property of the DOM Node interface that returns the first child node of a given node. It yields a Node object or null when the node has no children.
Because the DOM represents all node types, firstChild can be an element node, a text node, a
firstChild contrasts with firstElementChild, which returns only the first child that is an element node and
For example, in HTML documents, document.firstChild may be a doctype or a text node, while document.documentElement
The property is read-only in the sense that you retrieve the node; to modify the children, you