The firstChild property is also called the nodeValue property. It is used in web programming to create the required statements necessary to initiate specific commands. When you create a first child, property you can easily detect whether or not the node has any children.
This is because the value of the firstChild property relies on this and is null when there are no children. However, if a node is a document, the Firstchild property then returns the first node in its direct children list. The property retrieves the first item from the child nodes and then works its way through.